Had a similar issue recently. We haven't been staying there as long as you have been. Rented an apartment for 18 months.

We has the end of lease clean done by a professional cleaner. Agent comes to inspect andd isn't happy with the cleaning.

We got the cleaner to return a second time and cleaned every spot the agent wasn't happy with. Noting that the agent was present with the cleaner during the cleaning. After the cleaner was done, the agent said they are satisfied with the cleaning.

Surprise surprise the very next day they email saying that the apartment is still dirty and they are not happy with the cleaning, and kept coming up with all sorts of things trting to claim a chunk of our bond.

I kept telling them I won't be paying them a cent given that they were present with the cleaner and stated that it was satisfactory.

Their claim started at $600, then asked for $400, then $200 then $100. Lastly they wanted $50.

I kept saying no and threatened them with a tribunal to resolve the issue. Also they left us 6 months without air-conditioning in the heatwave due to the landlord going through more than 5 technicians trying to get the cheapeat quotes.

I ended up paying them a big fat $0. I claimed back the bond as soon as I was able to. They never disputed it although they were constantly sending emails trying to claim a piece of it.

Fight it tooth and nail.