Wells Fargo Home Mortgage Company WFHM Won't supply correct payoff amount in a timely manner Des Moines, Iowa

I'm at the end of a very long mortgage refinancing process.  The attorney for my new bank requested a payoff letter from my existing lender, Wells Fargo Home Mortgage.  The amount they received is incorrect, because Wells Fargo failed to apply a payment I had made. Despite numerous efforts, phone calls, faxes, etc. over the last week, they still don't have this resolved, even though they admit that the made a mistake, they won't generate me a payoff letter with the correct amount until it goes through their system.  Unfortunately, that will be too late.

Time has run out.  I can either choose to cancel the closing and therefore have to resubmit financial documents, or pay out of my pocket thousands of additional dollars to Wells Fargo and wait an undetermined amount of time to be refunded.

I find it hard to believe that there isn't some way to do this and go around their "system".  If they wanted to resolve this and help out a customer in a difficult situation, I'm sure there is something they could do.

Why do we allow banks to get away with this kind of stuff?