I was with my management company for 2 years and now I discovered I'm not under a lease agreement... the problem that I'm having now is I have had a pest issue in the apartment for the last 7 months and they have failed to do anything until recently and since I've found out I'm not under a lease agreementthey have stopped work... under my lease if I have written letters and demanded work I can reduce the rent by half or $500 whichever is more per Chicago landlord tenant agreement we had at the first lease signing what right would I have now?? Please help

How much to you want to be moving soon? Month to month all they have to do is tell you they don't want to continue renting to you. SO while its fine to let them know of problems, and you can expect them to take reasonible measures to correct them... expect that withholding rent can and likely will backfire on you.

I will be moving on June the 3, 2013 I just gave my 30 day notice... I need to know because they informed that I will not receive my $2100 back plus interest for my security deposit...
How much to you want to be moving soon? Month to month all they have to do is tell you they don't want to continue renting to you. SO while its fine to let them know of problems, and you can expect them to take reasonible measures to correct them...expect that withholding rent can and likely will backfire on you.

I will be moving on June the 3, 2013 I just gave my 30 day notice...I need to know because they informed that I will not receive my $2100 back plus interest for my security deposit...

What reason did they give you for this? All you were required to give was 30 days since you were month to month.