Touch screen unresponsive after ios11

I upgraded my iphone 6s via wi-fi to ios11 and the touch screen stopped working. I tried to downgrade it in iTunes with and without recovery mode and it keeps installing ios11 and doesn't let me choose a backup. I even tried to download a firmware of ios 10.3.3 but iTunes won't let me choose which firmware to install. Now all my data is lost and I can't use the phone at all. What can I do?