You purchased the 2007 edition, right? The book should have the instructions for how to access the tests right in it. If the instructions aren't there, check the date - you may have purchased an older edition. If the instructions are there but you're having tech difficulties then, yes, tech support would have to help you. Are you sure you spelled everything correctly in your email to them? They're usually very prompt in replying to emails - usually within a day or two.
The email address is:
techsupport@manhattangmat.com
You could also cc
studentservices@manhattangmat.com and ask them to make sure tech support gets your message.
Or, if you want to call instead, you can dial 800.576.GMAT from anywhere in the US and Canada or 212.721.7400 from other countries.