Problem with GPD Win2

Good day to all, I do not know where to turn about my problem, for this I write here. (please forgive me in advance for my English, I know it weakly - I use an interpreter)
Technical support on the site does not work, calls to Skype are not answered, in the official GPD store on Aliexpress you can not even contact the seller.
In the official page of the GPD on Facebook, the answers to the letters are very strange (I can post correspondence).

Now I'm talking about the problem:
Has got to itself through Aliexpress device GPD Win2.
The device really liked it but revealed a small defect - the left analog stick does not work correctly, it works only in the directions top-right and bottom-left, in other directions it does not work. All other buttons, right analog stick work well.
The seller reported this but did not send him back (he waited too long for it to come). I decided to turn in the service for the repair of consoles / phones for diagnosis. There they diagnosed it - a problem in the left analog stick.
I ordered new sticks for Aliexpress, waited for them to be delivered, installed a new stick instead of the left stick - the problem remained. Again sent to the same center for diagnosis - they put the same diagnosis.
I had to open the device myself and simply swap the left and right analog stick. It turned out that the problem is not in the stick itself but in the board that is responsible for the gamepad and keyboard operation.
I'm talking about this board

Now I would like to hear a reasonable answer about the correction of this problem.
I wanted to buy this board separately - but I do not know with whom I can contact on this account (I wrote about the feedback system at the beginning of the topic).
Who can you possibly contact about the warranty for this device?
I can not return the device to the dealer - it took a long time, plus I engraved the letters of my language on the keyboard.