Who is responsible for lot rent after a bank foreclosure?

I am in a situation where the lender foreclosed on a mobile home in my park and sold it right away without notifying the park or management. There is a large back balance for that lot. The new person who bought the home at auction is trying to tell me he is not responsible for all the rent that is owed on it and only wants to pay for the few months the bank had possession of the home? Can I force the new owner to pay the back rent? Can I put lien on the home if he refuses to pay?

The first question is have you screened the new owner of the home.
Until you screen him and accept him as a resident he can own the home but is not permitted to enter the property or reside in the home. He may own the home but until he is accepted and signs a lease he is not a resident. If he has moved in already start the eviction process before screening.
As for back rent it was your mistake to allow it to get out of hand without immediately evicting. The new owner is not responsible for your mistakes. You have to go after the original owner and the bank not the new owner.
Be professional about how you handle the situation but keep in mind the new owner is not responsible for this situation. He bought the home in good faith you simply need to work through the process but do not relax your screening process simply because he already owns the home.

The new owner is a wholesaler who buys and flips homes to mobile home park owners so he will not become a resident. The odds are high that when he sells this home it will be removed from the park. I am upset about 2 points here. The first being that I was not notified that the bank was going to auction this home and not giving the park a chance to bid on it. Second, Now that the home was sold to this wholesaler he wants a large sum of cash for the home. Basically at this point if I do not work a deal with this guy he will resell home and the new owner will want to pull the home. Disregarding the balance owed before the foreclosure what are my options here to get the money owed and keep this home in the park? Was there any laws broken in this process?

Do your community rules allow you first right of refusal on any homes in the community being sold or is it written into your state regulations that community owners have first right.
If so then you have a case against the bank to stop the sale even after the fact. If not then keeping the home in your community will require that you purchase it yourself and resell.
Your only option to get the back rent is to take the previous owner to small claims court.

Call your state MHA. They should know. If you can lien the home you might be able to prevent them from pulling it.

Like Greg said, why didn’t you evict a long time ago then start the abandoned home proceedings?