Repairs actually breaking phone

I took my Samsung A80 into the MTN store in cradock to be send for repairs as my phone gets extremely hot when it charges and at times the lock button does not want to work. My phone had absolutely no scratches or marks on it when it was handed it. Yesterday I received a call from the samsung repairs offices informing me that the warrantee on my phonr have lapsed due to the LCD being cracked, which was a huge shock to me as there was no physical damages to my phone when I handed it in. The MTN store confirmed that the phone was still in the condition of a new phone, this I have in messages on whatsapp from the lady from MTN. I received photos of my phone, or of the which is supposed to be mine, but does not look like minr as it has damages everywhere. My screenprotector had a light crack in the middle and that is all. Now no one can tell me whats happening with the situation