I just spoke with the manager at the bank where I made the deposit. They are giving me a provisional credit while their research department looks into it, she said it should take about 5 business days. She also said any charges that come from the error will be reimbursed - including any stop payment charges. Therefore, I guess if worse comes to worst I get Western Union to refund the MO and push to get Wells Fargo to cover the $15 fee?

Thanks for your guys' insight on this.