Some people have reported this issue fixed after re-flowing the appropriate solder points as described here. That’s the first thing I would try.
If that doesn’t work, it sounds like you’re in the same boat as I am. I think I fried the touch sensor on my LCD (which otherwise works fine) by seating it on the wrong pins during installation. Re-flowing the solder did not fix it in my case.
I have yet to try another LCD because apparently there are some driver related concerns depending on the exact screen being used (see here).
I’m wondering if anyone can confirm a replacement touchscreen LCD that works. The one officially recommended here unfortunately does not ship to the USA.