4th Xperia 10 unresponsive screen

I have a Xperia 10 and X 10 plus. I know this has been discussed on JT a lot of times but it is driving me cracy:
I sent both devices back and got new ones, without any change. Both are sometimes unresponsive (touchscreen) even after a reflash. I just reflashed and could not even enter the lock code.
What helps: Staying on the fingerprint sensor
laying the device down
pressing power on and off several times
bending does NOT help
this is driving me nuts. I’d be glad for ANY help, tia
seems this has been a problem since Jolla1