Registration key not working

Hi - I purchased the full package and was given a registration/activation key. Each time I insert it - tells me incorrect??? I cannot find a ‘human’ at Avast to deal with so getting frustrated and desperate. Plus it keeps telling me I have so many days, now hours to register/update.

HELP pretty please?

Sue Grant

how to insert license http://www.avast.com/en-eu/faq.php?article=AVKB7#artTitle