Touch Touch sensor responds incorrect

[abaha4i]

Hi! I have bought my Kobo Touch N905 not new (seller told it was unused, but it's not true). I checked it on post, opened a menu, a book - all worked. Later I noticed, that Kobo worked slow and made factory reset. After that I suffer.
Touch sensor works randomly. I need to tap a lot of times to open menu or book. Pages turn in random directions. I opened "sketch pad" (it was hard) and tried to draw lines and dots - results are on photos.
I tried to load all versions of firmware one by one, but this bug stays.
Once the problem has gone. I even have drawn a circle and straight lines in "sketch pad". Then it came back.
I have found many similar cases on the internet and no one solution, that works for me. If you have any thoughts about it, please, help!
P.S. Sorry for my English

P.P.S I made a thread in wrong forum. Can moderator place it to common forum, please?