Very good analysis and suggestions by William.
And I'm not a lawyer, either, so this isn't legal advice. However . . . .
Regarding the validity of your lease (and thus your obligations and those of the owner or the owner's representative) It's totally irrelevant whether your landlord committed forgery.
The questions are: (1) Do you have a valid lease? And (2) Are you and the owner in compliance with the lease?
You need a lawyer to sort out the issues, and to focus on the relevant facts.