Hello everyone I have been having a store that's been breaking even, which I guess is ok. Over 300 orders and going up, I had my first problem about a certain order. I sent shipment out to a customer and after a few days USPS says it's been delivered. I got an email with the customer saying they have not received it, I emailed them back showing the tracking number from the USPS website. They claimed they did not sign for it and never seen it and if they dont get their product they want a refund. The item they order was small (about $15) and they never requested a required signature on delivery. What should I do? Is it my fault. Should I tell them to contact USPS?