Complete history of my interaction with Mantiz regarding my order of a Saturn Pro II.

2020-11-10
I order a Saturn Pro v2 directly from mymantiz.com after finding it not in stock via Amazon.
2020-11-18
After a week of my order not shipping, I send a request to Mantiz asking that my order be cancelled so that I can wait until it is in stock with Amazon and avoid the $60 shipping charge.
I receive an immediate reply (40 mins later) saying that it is going to ship the following day from Taipei and asking if I would like to wait.
I reply three minutes later asking if, when you restock your Amazon listing, whether there will still be a large $60 shipping charge.  No reply.
2020-11-25
After a week of no further reply from Mantiz support and no shipment notification, I conclude that the order was cancelled.
(I had not yet noticed that my payment of $389 was drawn from my checking account via PayPal on 11/12 and never refunded.)
I see that it has become available via Amazon again and so I place an order with Amazon.
2020-11-26
I receive a notice that both my Amazon order and my direct Mantiz order have shipped.
I send another message to Mantiz support asking what is going on and why my order was not cancelled.
I receive an immediate reply that I should just refuse delivery with USPS to have the product returned.

USPS reports that they are still awaiting the item from my direct Mantiz order.
> Departed Shipping Partner Facility, USPS Awaiting Item, LEBANON, TN 37090  Shipping Partner: AMAZON
> Your item departed a shipping partner facility at 12:23 am on November 26, 2020 in LEBANON, TN 37090.
> This does not indicate receipt by the USPS or the actual mailing date
2020-11-29
I receive the Saturn Pro I ordered from Amazon.
I set it up and after a couple of days testing and troubleshooting, I discover that the fans are too noisy and irritating to put up with.
I request a return and write up a review describing the problem in detail.  Amazon issues a full refund on 2020-12-03.
2020-12-03
I see that USPS shipping status of my direct Mantiz order hasn't changed from Nov. 26th – they're still waiting for it in LEBANON, TN.
I send this information to Mantiz support via email and ask about my refund.  No reply.
2020-12-05
I receive another Saturn Pro from Amazon.  (not the USPS shipment for my direct Mantiz order)
I did not order this additional unit and Amazon shows no history of it but there’s a receipt inside that says it’s from a 2020-11-24 order with a different ID.
2020-12-07
Reply from Mantiz support: "We need one more day to check with our logistic team. Please kindly wait for awhile."
2020-12-09
I send a follow-up email.  No reply.
2020-12-11
I send another follow-up email asking for a response.  Still no reply.
2020-12-14
I send yet another follow-up email and also a message via their iMessage contact.  Still no reply!!
2020-12-15
I post an explanation of the situation to the eGPU.io forum, where a Mantiz support person sometimes interacts with customers.  (As a new member, I wasn't allowed to send a direct message to the person.)
2020-12-16
I send a direct message to the Mantiz support person (Mymantiz_John) on eGPU.io now that I had permission to do so.  No reply.
2020-12-17
I report the problem via PayPal as an item that was never received and attach the invoice and a description of the details, including the fact that I received a duplicate Amazon order.
2020-12-18
I contact Amazon to ask about this extra delivery from Amazon.  Amazon does not know what it is and does not recognize the order ID format.
UPS says that the item shipped from Amazon in La Vergne, TN.
I send another message to Mantiz support with pictures of the shipping labels and the enclosed Amazon-like invoice receipt asking if this is indeed my direct order even though the order number, order date and tracking number don't match my order.
2020-12-27
I receive two replies from Mantiz: one via my PayPal inquiry and one via my email message from Dec. 14th.  Both explain that the item I received from Amazon was shipped by them through Amazon fulfillment.  They don't say anything about how to return it.
I reply via PayPal, their support email and the "alexlin" email provided by PayPal asking how to go about returning it.  I explain again that I requested it be cancelled a week before ever receiving the shipping notice and that I have not opened the Saturn Pro box.  I also provide a link to this history page.
2021-1-02
I escalate my open case with PayPal, explaining that Mantiz says the Amazon package I received via UPS is my missing order but Mantiz still has not responded to my request for a return and refund.
2021-1-05
PayPal closes my "package not received" case based on the fact that I received the alternate shipping of the Saturn Pro. (At the time that I opened the case, I did not know that the product I received was from the same order.) No comment is made about my attempts to return the product and get a refund.
I try twice to open a separate case with PayPal to report my failed attempts to get Mantiz to let me return the product, but both fail. PayPal apparently automatically closes the case when I report that Mantiz has yet to promise a refund.
So I send another email requesting a return and refund to Mantiz support but using a different email address.

Surprise! I receive a reply to my more anonymous email address asking for the order number.  I reply with the order number.
2021-1-06
Finally! I get a reply from Mantiz support with a return address and the comment: "We'll check the quality once we received."
Unfortunately, the return address is in Taiwan and there's no mention of handling the return shipping or the refund.  I expect that it'll be very expensive to send it all the way back to Taiwan so I send a follow-up email asking about this, reminding them that the product is unopened and asking whether they will provide a shipping label to ship somewhere more locally, even perhaps another customer nearby.
2021-1-12
No reply from my last message to Mantiz using my alternate gmail address.  I send another email documenting the expense to ship it back to Taiwan via various carriers (cheapest is $104 with EMS Parcel Post).  I also told them that I created for sale ads with craigslist and egpu.io to try to find a local buyer.

No reply ever since.