Chosen Solution

I was fixing the back and I accidentally cut a cable but I don’t know what I cut and how to fix it and when I make calls I can’t be heard

Sounds like you need to replace the lightning connector. There should be a guide on ifixit on how to replace it. Just make sure you’re using an OEM or premium replacement. The X and above are picky when it comes to aftermarket chargers and will restart constantly if you use an aftermarket.