Pre-foreclosure under contract but auction is in 3 days. Help

[Jesus Valdez]

Hey guys. We have a pre foreclosure deal in AZ under contract for 120K she owes 93K. The property is supposed to go to auction in 3 days. She needs to pay the lender 11K to stop the auction. I have 11K to stop it but I am concerned that after paying the 11k there is nothing to stop the owner from backing out of the deal and breaking my contract. Is there anyway to make sure the deal goes through after I've paid that money? Any advice would be helpful.