Community Tip - You can change your system assigned username to something more personal in your community settings. 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.
