Breach of Contract

I called Wells Fargo to see if they would accept a payoff of 70% on my credit card.  The representative said "yes", asked if she could record the transaction and supplied me with a confirmation number.  Wells Fargo took the agreed upon settlement from my checking account.  They then informed me a supervisor overrode the agreement and they would be returning my money back to my account.  Can they change their mind on a contract?