Two points that come to mind, first: to get a motion to compel production in front of the judge (good time to assess the judge's attitude about your case), second: consider asking for mediation (if not agreed, then ask for court to so order).
Also, I am not at this time the lawyer for you and I am making assumptions about the facts. I am easy enough to find to talk this through. But, if you were in my family then I would want you to have local counsel.
The foregoing comments are provided for informational purposes only, and without a fee agreement and fees paid there is no attorney-client relationship being made and no legal services will be provided now or later.
It will be easier to contact an attorney versus waiting for a good answer to your very specific question with unanswered questions.
In short, agents can sign for landlords. You need to make sure you sue the right person. It's probably a good idea to hire an attorney.
The above statements are provided as general information and not intended as legal advice. Each matter has its own set of unique circumstances that cannot be adequately addressed without consultation. You are strongly advised to hire an attorney licensed to practice law in your state to represent you.