Apartments charging 5k after move out?

Location: Washington state

Moved out on the 17th of January, and lived there for 2 years 3 months (1 year lease, then a 15 month lease) just got a random email from them saying we owe 5k for damages.

No invoice received even though they have stated they placed it in the mail on February 3rd. They claim they do not have tracking on it. The 5k was due to carpet replace, yet all photos show no damaged carpet, and we steam cleaned the carpet before we moved out.

Office manager claims there was also unpaid rent after we had paid the total on the first. The invoice is showing that things were posted for the 1/2-1/17. All rent is supposed to be posted on the first, and the manager could not explain why there was extra rent.

I guess my question here is what do I do? I know Washington law requires them to have sent something within 30 days and they haven’t. In my emails the manager said she has no tracking on the mail sent on the 3rd, so I highly doubt something was even sent. I’ve already started to request all invoices and paperwork I can from them to look over with my father tomorrow.

Any other advice on what I can do would be great. I unfortunately don’t have photos, and my roommates have been unhelpful during this process (I basically lost my best friend of 11 years during this move out but I won’t get into that here). I am trying to get them to send me their maintenance requests and any photos they have but so far they haven’t sent anything.