Odd tenant situation - what would you guys do?

[Matt C.]

I've got a weird situation with a tenant that I'm not sure what to do. I recently bought a 2 flat in Chicago, and the leases from the previous owner were a complete joke with no security deposit. One of the tenants moved out and I moved into the apartment. They didn't pay their last month's rent and there is no security deposit. Per the lease, the tenant was supposed to have repairs done themselves, save receipts, and be reimbursed. This tenant said the repairs in total were the cost of the rent, but hasn't given me receipts for the repairs, so I cannot take them back to the previous owner to be reimbursed. I didn't want to serve the tenant with a 5 day notice because supposedly it could make it harder to get the tenant out of the building at the end of their lease (the lease was up at the end of that month). At the time, I was just happy they moved out, and figured I would take the receipts to the previous owner and get reimbursed for the missing rent. 

The tenant hasn't gotten me the receipts and won't answer any calls. So, I'm basically left without that last month's rent. I had originally just chalked the missing rent up to the cost to getting the tenant to move, but am hoping now that there's some possibility of getting the rent. The rent is $1,000 and I'm thinking it would probably cost more than 1k to get the money. Any ideas?