breaking a lease and security deposit

[John Kilkenny]

I live in virginia and own a rental property.  Tenant has a two year lease and is breaking the lease - no cause on my end, they lost their job and got a new job out of town.  I have no problem breaking the lease - but they changed their move out date 3 times, making it hard to rent until they move out.  The tenant just asked me about returning the security deposit....I checked the laws and they don't seem to have cause.  The only way they could have cause ( as I see it, and read the laws)  is if I made the home unlivable, was abusive, or they were a military transfer.  None of this is the case.  

am I missing something - they broke a 2 year lease 7 months early, and have no claim to the deposit as far as I can see it..... 

thoughts?