Had this happen to me. There was a small stain on the carpet that could have been removed but I ran out of time moving out.
Apartment kept my deposit and told me I owed them $2k to replace the entire carpet. I ignored them because I looked up the carpet, and it was $0.49/yd. All together it would have been less than $500.
Got sent to collections, and I told collections I'd pay if they could provide proof of $2k in damages, which was legally required in my state. Never heard from them again.