Tenant Moved-out a few days early and want credit back in rent?

[Maggie Ng]

06/03/19- 1 of 5 tenants emailed stating they will submit their last payment (due on 7/15/19 for the last month of their lease of 07/15-08/14) and everyone will be out by the end of the month. 

06/15- Tenant Paid for last full month while knowing it would be vacant by the end of the month. 

06/17- Tenants texted me they'll be cleaning up this week and moving out and everyone will probably be out at the end of the week. And mentioned if there will be a new tenant occupying, they felt it would be fair they get a credit back in rent. 

06/18- Tenant e-mailed me stating everyone has moved out and called the day before to say keys are in the drawer. 

06/19- New tenant moves in. 

I have sent the security deposit back to them in a timely fashion(which they already accepted) and only deducted 1/2 the cost of damages in the property since they were so cooperative in their move out, which I regret already. Now they are calling and texting me stating they want the 2 weeks of 08/01-08/14 back in rent. I've spoken to a lawyer and he explained that the tenant forfeited/surrendered the property the moment they returned keys and they were in no way obligated to return possession prior to the end of the lease. From my understanding, once the tenant returns possession, the lease agreement is terminated. I understand the security deposit is different from this rent credit they are requesting for. My thought process is the same as the lawyers. I'm not sure if the notice on 6/3/19 counts as a 30 day notice since the lease states all notices must be sent to my address but then this would invalidate their move out. I also understand Michigan Law requires that a landlord makes effort to re-rent the premise in the event of an early termination and tenants are to pay for the cost/loss until a new tenant is found. I also had to pay my agent 1 month rent for commission which it seems like the 27 days they've paid for would just about cover. However, this is unique in that it isn't an early termination and we did not require them to vacate early so I'm iffy on how to approach this situation. They are now threatening to reach out to a lawyer. I am pretty confident in my rational but I'd like opinion from others who may have experienced this situation or any legal input! 

[Ray Harrell]

You don't owe them a rent credit for the remainder of the month UNLESS you happened to rent the unit on the day they moved out. You can't collect rent from two parties on the same unit for the same days. If they left early, that's on them.