My phone screen has just cracked by itself, was only fixed 2 days ago

I got my phone repaired on Sunday last week (2 days ago) and after i got it back I noticed a couple of problems. First off, the screen was slightly disconnected at the top, but nothing was exposed and it didn't seem to be loose so I thought nothing of it. The second thing was that it felt harder to type- sometimes it would type double letters or add on ones I didn't hit. I chalked this down to my fast typing.

However, today I was using my phone, looked away and when i looked back down there was a large crack (diagram attached) on the screen but the screen protector was completely intact. I hadn't touched it at all, and i wasn't anywhere where I would have hit it against anything, or suffered any sort of impact (I was sat on my bed with the phone on the mattress). I feel like paying for a new one even though I'd already spotted faults which I can now link to the screen repair is pointless, so what should I do?