I own a business that fixes certain equipment. I have a customer who prepaid for their PM service and parts with ACH. The parts were on back order and I let them know when they had been shipped to me. At that point they cancelled everything and asked for a refund. I returned the parts and got my refund. I have asked them where to send a check for their refund of my labor and parts several times, but they just won’t respond. At what point should I stop trying to give them back the money and just keep it? It’s been about 2 months. #business source