Landlord asked me to return some of deposit 6 months later, what are my options?

I do the bookkeeping for some apartment buildings including security deposit refunds. I definitely include a receipt for every single deduction that includes the address as phone number of the vendor: it’s the law where I am.

Our leases list carpet as having a 7 year life, so that after 3 years on new carpet, a tenant would never be responsible for more than 4/7 of replacement cost if it was beyond cleaning. It’s unusual to damage carpet this badly, but it does happen - besides burns/candle wax/pet damage, sometimes people try to clean a spot and use a product that leaves a bleached spot. 90+ percent of the time, the carpet either can be cleaned or is older than 7 years if it needs to be replaced. We do a walkthrough before move out to give tenants the chance to fix stuff or at least be aware, but sometimes there’s stuff we can’t see because of furniture or the tenant leaves junk that needs to be hauled away, leading to additional charges.

I honestly don’t know about the additional $500. This is exactly why I pull out the original lease every time I do a return just to avoid a mistake like this. I think I would not respond at all and wait to be taken to small claims court, which I think is unlikely to happen unless this is his only rental unit, and his margins are super slim. We had one tenant who did so much damage that he owed an additional $800 on top of his security deposit (very very bad dog.) I checked the boxes on the form that said he should send us a check, but we never pursued it … not worth the hassle. He knows better than to use us for a housing reference.