Duct cleaning in general sounds like genaral maint/ fair wear and tear... so part of the landlords obligation.

Without looking at all the details it is impossible to tell if this is legit. If the lease agreement allows for the charges then it is just some...

Mr. Lautin in correct, however if you recognize that he is behind on rent, without a legitimate defense (tough times isnt a defense) then he will...

Mr. Lautin is correct, you can ask for a continuence of up to 7 day, but you can also empower an agent to act on your behalf (attny, friend, etc)....

Mr. Cowan has outlined the issues quite well. I would start from there and then speak directly with an attny licensed in the country/state (forum)...

You can discover easily if he is a licensed plumber. If he is not there could be some legal issues for him. Whether he is or not you can always...

You can file a civil claim at any time and file a police complaint at any time (good luck on that one).

Seek the owner (its a registered property) inform them of the issue indicating you will consider it abandoned if there is no timely response and...

Yes, nothing wrong with it, but Mr. Jeffries raises a good point.

Thus depends on the facts... reguardless of when you vacated and gave back the keys there are valid reasons a landlord could bill you for longer...