Help with Digitizer

I took my torch to get the screen flex replaced, now the issue is that the proximity sensor sometime is being block by the digitizer it seems to be a little loose any ideas what to apply to get this issue fixed if i push on the digitizer the problem will fix put only for like an hour or so. what happens is as soon as i make a call the screen go blank and i cant touch the screen nor no in call options until im done with call.

There's double sided sticky tape that hold the digitizer to the lcd. I would say when they replaced the screen they pulled the digitizer off the lcd and didn't replace the tape and used the old to save some dough(never works properly again once you break the seal(I know I did this myself and ended up replacing the device). I would take it back to where you got it fixed and have them replace it.