I too have order the MPEG2 license and, after more than 72 hours, have not received anything other than an automated reply. I have sent two messages and have not received a reply. Very disappointing.
If you are going to advertise something for sale, and claim to process the order within a specific period of time (72 hours in this case), well, you should make certain you are able to do so. If you don't have that level of competence, replace the 72 hour promise with a message stating: "quit whining and we'll get you your license key when we get off of our duffs and feel like doing some work - otherwise, bugger-off"
Just be honest and don't deceive your customers.