Check not cashed! I don't want to loose my place.

I am renting my rent-stabilized apt. for 3 years now. I just had someone move in with me. Due to their move, I had to put some things in storage. Super called LL and said that I moved out and that a new person moved in. I mailed my check as usual but it was still not cashed. I called the LL and he said he send my check to his lawyer, and that he has no time to talk to me. I tried to explain that I have no interest in leaving my apt., but he said that they believe that I did, since the super didn't see me in a while, which is not true, every time i go knock on super's door, he is not home.
What would my action be to prove that I do live in my apartment and some furniture modifications were made, i don't want this to get ugly and don't want to loose my place.
Thanks

[OHlandlord]

You will just need to prove that you still live there. Are the utilities still in your name? Does your mail still come addressed to you at that unit? Do you have a receipt for the new furniture? Copy some of these and send them to the LL with a letter that explains that you did not move. Explain that you bought new furniture and got rid of some old stuff, but that you are still living in your unit. Send this to him by certified mail, return receipt requested, and keep a copy. This sounds like a simple misunderstanding. And make a point of stopping by and letting the super see that you are still there.

The other problem is having your friend move in with you. Does your lease say you are allowed to do this? Are you required to have any and all roommates approved and registered with the LL? Are you allowed to have a new roommate under the rent stabilization rules? Or does this violate the rent control law? If it does, you may be removed from your rent controlled unit.