Unauthorized lease terms signed by unlicensed onsite manager

[Alice Yip]

Does anyone have any experience similar to this: I signed an agreement with a real estate salesperson to manage my property.  He had a managing broker for his sales transactions and he tries to keep his property management business separate.  He used an unlicensed onsite manager at my property.  Several months ago, the onsite manager entered a long term lease (several years) without the knowledge of the real estate salesperson or me.  The onsite manager was recently let go and I just found out the unauthorized lease.  Also, the tenant has prepaid rent for the entire lease term at a ridiculously low rate ($10k-15k) and the onsite manager has taken off with all the money.  There is no lease agreement but simply a handwritten receipt by the manager acknowledging the amounts and the dates that the tenant supposedly have paid for with the manager's signature.  What is my recourse?  What is the tenant's recourse?