Renter wants to get out of the 12 months lease in 15 days

[Abhijit Roy choudhury]

I recently leased an apartment to a couple for whom all credit check and background check checked out fine through smartmove.com. They paid 1 month security deposit and said will pay the rent when they move in on 1st of October. They did not pay the rent and now have changed  their mind and have decided not to stay here and want out. It is a 12 month lease. Can I legally enforce the contract and require them to honor it? Is a legal step recommended? Any suggestion would be helpful.