Already subscribed to avast 10 months ago

would like some help with my subscription.
Have had trouble with my computer and lost my subscription which is still in order till end December 2014 but I am being asked by my computer to update my avast and will be charged. Sent a help email to Avast and they sent me here
anyone know how to get my subscription back
Debbie

http://www.avast.com/resend-license-paid.php