Do you have a written agreement?

Review their management agreement.

Your offer to purchase should include a requirement that the Seller provide all documentation and agree to sign an estoppel certificate (also called an estoppel form or agreement).

We have a clause in the original contract saying that if they cannot get caught up on payment by the end of the 6th month, the lease agreement will be terminated.

In signing up for their service which is called "PIN" I signed their online agreement but I made sure they had a rescission period. 

I had to give 30 days' notice per our management agreement to a client I have 13 units with on Friday after having to hang up the phone on him Thursday afternoon and telling him if he ever speaks to me that way, it will be our last conversation.

I am looking for some help getting a liability agreement set up for my new short term rental.

Any thoughts as to using the Lease extension vs Lease agreement form?

I have a signed purchase agreement with the seller and have proof of being able to go through with the purchase on my end (financing good to go, title company set up, etc.).  

A non-disclosure agreement (NDA) is an agreement document that creates a confidential relationship between parties who will be exchanging confidential information.