Section of iPad Mini screen unresponsive after screen replacement

I have replaced my iPad mini screen and whole back housing. The whole repair went perfect but after a day I realised that a small rectangular area near the time (on lock screen) is unresponsive. I need to know the resolution to this problem.

Also a side note the 3G signal is now not getting service where it did. It was working fine after the repair but ever since I re-opened the device and pushed on the top antenna connections it's now not getting service where it usually was.

I NEED HELP ASAP!!!