Having had my go rounds with a bank over supposed non-payments, I sent them copies of all my money orders and suggested they trace the money orders through Canada Post to see who cashed them, when and where. The account number was clearly printed on the money order so no excuses were to be tolerated on my end. Lo and behold it was cleared up in 24 hours when they saw my evidence.

I never send originals, always copies. I don't trust anybody.