There is an EZdrummer to S2 Crossgrade available. Currently, however, the crossgrade is more expensive ($5 more) than the Regular version since Toontrack is offering a 30% sale on the Regular version of S2.
There is no phone number offered on emailing because Toontrack doesn't offer phone support. You should be able to contact them directly via the FAQ.
Can you access the Contact Support button at the bottom of this FAQ below?
http://www.toontrack.com/faq/m.....what-next/
If not, what Internet browser are you using and what is the version number? I can forward the info to the webmaster.