Loft Building Issues

[Shamus]

I have a commercial lease on a loft that has come up for renewal. It is a non-regulated apartment. Last year the rent increase was 7% and this year they want 3%. The building, as of March 2002, was rezoned for Residential use, but the LL has yet to convert any lease to residential. What rights do I have now that I know it is residential as opposed to commercial? Also, the rent increase has been given without any notice or any type of new lease agreement.
Also, when tenants of this building signed the intial commercial leases, the LL said our interest on our deposits would not be given to us. I believe, as many people in the building do, that this is illegal and the LL loses his rights to the deposit money and the tenants have the right to it back.
Please give suggestions or ideas for negotiating with LL. Thanks.