Care to elaborate? To my understanding the old "postmarked" thing went away with the rise in electronic billing and companies must actually RECEIVE the check by the due date, or they can charge a late fee. The USPS has become notoriously unreliable over the last several years. I REFUSE to mail a check because it has EVERYTHING someone would need to set up fraudulent transfers, so when I had a bill that needed to be paid via USPS last year I sent a money order certified mail, it took 6 weeks to be recieved. It was NEVER scanned as delivered as the USPS was no help, they said "oh it probably got delivered and they forgot to scan it."