Messed up touchscreen firmware on latitude 7320 detachable

Hello!

I got this lovely tab, used, earlier this week for a very nice price (about $300), but when it arrived the back camera was not working. The seller is very far and sending it back for a fix would have cost me almost 30% of the price I paid, so he advised me to update ALL drivers, including bios and whatnot.

Dumb me used Google to look for drivers and one of the results was this

https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=n3j44

A firmware update for wacom which was "not compatible". However, having gotten away with installing touchpad and GPU drivers from other manufacturers in the past, I figured that if this is not compatible it won't install, right? WRONG!

It flashed successfully and rebooted, but now the touchscreen works funny: imagine a line that splits it vertically in the middle. If I touch on the far right it will register on the same position on the far left, and if I move my finger towards the center and up or down, the touch will mirror it on the other side. So basically, left is right, right is left, but up and down are still the same.

Installing windows again didn't help, and the touch is even wrong in the BIOS! 

I tried installing the bios again and doing a last known good configuration but I was unlucky, so I came here for advice.

Thank you in advance.