Hi Worhin
Unfortunately, Grimefighter does not/will not work on some Systems. Also unfortunately, there is really no technical support for Grimefighter on this Sub Forum.
Pretty much only user input here.
You can go to
http://support.avast.com and "Submit a Support Ticket".
If you want to request a refund please provide as much info as possible about your case(s) at form
https://support.avast.com/Tickets/Submit/RenderForm/27/&cls01&ptf01&lic01&scr06 - select Refund request on left side.
If/When you submit, please be patient for the response and do not submit more then once and altering/modifying initial ticket will cause longer response time.
Process should take approximately 7 business days.