mudtone20 on Bought early copy of Ezdrummer that I cant on install on mac?

Hi bought an early copy of Ezdrummer around 6 years ago or so and used it for my Desktop. Now I have a macbook and I am also using a different email account now, because my old one was compromised. So I can't re-register my product. Need help!
Also to add I have the latest OS for mac El captain which wont even let me pass the install.