Advice needed for the arguement with the landlord

Should I insist to file a case and to get the deposit back?

The lease ends on July31th.
I moved out the apartment in the middle of July and left the room in a mess with clothing, books, and others on the floor. I didn't clean the bathroom, the ranch and the floor either.
Last weekend, I went back to clean the apartment and took all the things I left there. I found the worker hired by the landlord entered the apartment, and did the most of cleaning job and pile my things together.
I finished the cleaning work they left (bath tub and counter top)
When turning in the keys this morning, I asked when I can get the deposit back, and the uncle of the landlord refused. He said I left a mess and he had to let worker to clean the room before showing to potential tenants. I said, today is the last day, and if you want to show the room to others, you should inform me, and I can clean before showing. I told him I also informed the landlord 60 days before the end of lease. But he still refused.
Then I checked the local law. The local law says: The landlord has to inform the current tenant verbally or written at least two days before entering the apartment. But I never received the calls or received the letters. (I usually checked the mail box after several days although I didn't go into the apartment, because my office is near the apartment.)

I want get the deposit fully back, because they did cleaning work without my permission during the time that the lease is still effective. I could do cleaning work by myself if they inform me.

If the landlord still refuses, and I want to file a case, how sure I can win the case, and get the deposit back? Now I feel I just want to win the case, because this is the first argument with the landlord after my staying in U.S for 7 years. I feel it is very unfair he treats me this way. I almost move every year, and my rental history is very clear, I got deposit fully back for most of time, and only got charged once for $45 dollars due to the broken of the bottom of cabinet. But this history is in another state, and the apartments are owned by companies. But this landlord is a small family company, running by the son, the father and the uncle.

Thank you very much.