There is a debt that my ex-husband is responsible for that is affecting that.

Explain to them you will do your best to find a replacement tenant at the same rent they were paying, but they are responsible for their rent until such time that you find somebody.

I look forward to your response. 

Who is responsible in this case?

Thank you @Seth Lipper for the response.

You have a tenant you are inheriting and I will bet the portion that MHA pays is at least $750/mo and the tenant is responsible for the other $200. 

I put the address in and it gives me 20 responses, all not the correct address.

Do we send certified mail to our rental to see if it would get forward since I'm thinking this would have their forwarding address.It appears they are purposely trying to hide and run from their responsibilities and they probably know we can't just go walking on base to look fo them.So I want to file a small claims even though the max is $10k, lower total damages but still a ton of money we are out even if we do get a judgement. 

Once they go through all the usual responses - I heard no money....., "quick way"...., "easiest to get into real estate"...., I burst their bubble!

I think I probably would have had better responses if I would have posted the question to finance.yahoo.com  :(