Community Tip - Visit the PTCooler (the community lounge) to get to know your fellow community members and check out some of Dale's Friday Humor posts! X
This is a user forum and you will not get much specific help regarding Licences.
PTC Support Portal: You can open a case online through the PTC Support Portal. You may need to create a basic account first, but this portal is the central hub for all PTC product support. The portal explicitly states that if you have purchased Mathcad with maintenance and cannot locate your confirmation letter, you should contact them with your order details.