We live in marion county fl and signed a contract to buy a mobile home. We were suppose to use the first time home buyers credit as our down payment, but did not do so, does this make the contract void or does the lender have to forclose on us? She is now trying to evict us.

No, this does not make a mortgage void, they will have to foreclose ( or repo for a mobile home)

Once a real estate contract or a contract for sale on a mobile home is done, and all finance agreements and terms of the contract are done, the sale is final. The mortgage is merely an agreement to pay back according to the terms.

Your failure to get, or inability to get a purchase credit, does not void. It merely means you did not do what you promised or you were unable to get what credit you thought you could get.

You may want to reconsider and find a way to pay for your home.