You need to post your location if you want any actual advice.
Going by the terms you use, it sounds like you're in NYC. You can request a rent history for your unit by e-mailing
rentinfo@nyshcr.org along with your address. They'll mail you a rental history that includes what previous tenants have been paying in rent, and what the legal rent it.
If you think the LL has claimed extensive renovations in order to get an rental increase authorized, you can contact 311.