I believe you paid for that licence, right ? Then, all you have to do is to contact somebody from Alwil team or send an e-mail explaining your problem. I'm sure they will respond as soon as possible. You'll have to send your personal information as well as proof of purchase and that's it...
Here is the e-mail address you can use:
sales(at)avast(dot)com
Of course, replace AT and DOT with coresponding characters