If you are having trouble getting any kind of response from Avast in regard to your refund, I’d strongly suggest contacting the Better Business Bureau of San Mateo, CA. You’ll be surprised how fast you hear from them.
Avast Internet Security as far as I’m aware doesn’t come with the Full version of GrimeFighter that is a stand alone purchase. So presumably you purchased both products.
You can submit a support ticket for a refund for GrimeFighter - https://support.avast.com/ and use the Submit a Support Ticket - once you have done that post the ticket ID in this forum.
The OP, j89gossett hasn’t even made contact yet - but seeking advice on what to do.