What to Do When a Transaction Includes False Documents?

[Rachael A. Tanner]

I recently purchased a 2-unit property in Georgia. I live in San Francisco.

During the process, our real estate agent provided good service. Including providing the leases for the tenants that are in place.  I didn't do my due diligence of speaking to the tenants, though one had not actually move in yet. 

After closing I communicated with the tenants regarding change of ownership, new place to send rent, etc. One of the tenants produced a different copy of the lease that states the rent is $900 a month.  The lease provided by the sellers said the rent was $1,000 a month. 

Any suggestions what to do? Clearly someone is lying and I'm not sure who it is. 

The leases have the same date. There is only one signature page, though. 

Any help is appreciated!