I am in a similar position. I installed Avast Internet Security on my Windows 10 machine and have had so many problems since. I have now removed Avast and my PC is happy again. I have requested on numerous occasions (by raising a ticket with Support) for a refund but there is total silence from Avast. Nothing short of absolutely poor customer service, bordering on fraudulent. Avast, how about answering my ticket (#47545) and give me my money back.
I used to love Avast, that has completely turned around now with this experience.