If you think there is monkey business going on then have your agent inquire with the listing agent and as/if needed with the lender. You can also run a title on the property to see any liens - all which should have been disclosed or discovered.
If that fails to get answers, speak with the managing broker and have your agent elevate things up until you get answers.
You do have an experienced agent of course?
Banks are worthless as far as getting anything done but two years is nonsensical for an eviction. They have standardized procedures that are followed, legal action is typically involved and the listing agents tend to oversee it all. You are being sold a bill of goods. Atlanta has many nitwits that do this, the paper loves to write all about it - http://hankmillerteam.com/2012/12/07/occupy-atlanta-moves-in and it ends the same way.
You might also be a little careful, if the squatters are combative I've seen many homes vandalized both obviously and in ways you won't see right away. I'm a FNMA foreclosure appraiser as well, quite familiar with the theatrics.
Rodney is absolutely right, but if the bank has been "fighting for two years" to get a tenant out, something is very amiss there and I would move on if I were you. The tenant must have some kind of grounds. Just so you know, there is a law that if a home is foreclosed on and it has a tenant with a lease who is paying on time, the bank has to honor the lease - I not sure if it is for a year, or the whole term.
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