I don't know, phylray,
I sent Avast an email, to avast.fr@digitalriver.com - requesting a refund. But it's the weekend, so I don't expect a reply until next week. I've always had a lot of respect for their anti-virus software, and I was a happy user of the free version for about 20 years before buying the premium version, and then the Grime Fighter. It's hard to imagine that they will neither try to help me get it working or refund me if they can't help me, but who knows?
Did you write to the same email address? The email address above (avast.fr@digitalriver.com) is the one which included confirmation of my order and my password, but maybe we should write to a different service?? Maybe someone here will know.
Good luck!