how to stop paying rent?

I signed a 12 month lease, and was instructed to complete the early termination as follows: select option give 60 day notice and pay until new tenant moves in, vs 60 day notice plus two months. On July 15 I put in my 60 day notice and told them I would advertise the unit online, they called me on August 5th saying they need me to vacate the unit by the 11th if I want the new tenant to pick up my lease, which I did. After I gave the keys back to the office, they said the applicant backed out and they will lease the unit. I asked to make sure the unit is listed online as Available now . A week went by and they never advertised the unit. I called today and asked why, they said it was online but since there is an application the unit is out of the system, however if I want others to apply they can as back up. My concern is that I don't have a place to live, and they wont let me take the unit back, however they want payment. What can I do to stop paying rent.