Cannot update (despite having entered serial number)

Hi everyone I am using Cross DJ 2.1 and I get the notification of updating every time I open the program. However on the website it says access denied as I haven't entered my serial number, which I have entered a million years ago. I have learnt that this is a problem shared by lots of users and who should I send PM to fix this or there is no way to upgrade at all? I sent a PM to unclevibes a week ago but there isn't any response so far. Gutted.