Tenant backs out of lease

[Ronnie Sparrow]

Not sure how to handle this situation. I have a signed lease for a year and a deposit of $1,600, the tenants were scheduled to move in on June 5th 2015. I get a call today and tenant wants to back out of the lease now. What should I do. The lease is a TREC lease from Texas. Do I need something in writing from them? Do I keep the deposit and put it back on the market? Do I return the deposit to them and move on?

Need advice.