What happened to my phone?

Hi, my Samsung galaxy went in for repairs (the screen was totally black). Unfortunately, there are several issues once I collected the phone: 1: The phone is completely unrecognisable - as if someone else's phone has been returned to me. There are app installed that I've never used before such as Netflix, TikTok and even games such as Coin Master and Block Blast. These are NOT apps that are auto installed if a phone has been wiped clean. Who's phone is this? 2: I was asked to supply my login pattern which means the technician must have gotten the screen working again. So why has my phone not been retuned to me in the same condition that was supp****? 3: The back of the phone has been scratched to hell. I take extremely good care of my electronics. This is not the same condition that I handed it in (if it even is indeed my phone) 4: Stickers have been placed on the phone and charger that are extremely difficult to remove without leaving residue. 5: Pen writing and a sticker on the box meaning I couldn't;t sell this phone again if I wanted to.