I bought Grime Fighter for over a month ago, but it never worked on my computer, just got a black screen and nothing happened. Now it’s been updated (and for free) and now nothing happens, nothing. Not even a black screen. I want my money back, how do I go on to do that?
You can submit a Ticket and Request a Refund.
Contact Avast support:
https://support.avast.com > Submit a Support Ticket, follow through all options and explain your issue. 