Avast Software Refused to give me a refund. Software crashed my computer. Czech Republic Internet

I ordered A license for antivirus software. I was unaware that my laptop PC came with preinstalled antivirus software so when I installed the avast software it cost my computer to crash. I immediately phoned their customer service phone number and they were aware that the problem caused damage to my computer . I requested a refund only to be told that I needed to submittd a request  in writing and they would send me an email showing me where I needed to submit a billing ticket. 

I forgot to send the request right away   5wo months later, I did submit a refund request later only to be told that since I did not request the refund within the guarantee period that they would deny my refund.  If a product is purchased and and a company is immediately told that the product is incompatible then proper customer service is to refund the money.  I never used their antivirus software, I had to return the laptop to the store and get a replacement.  I feel that the company scammed me out of my $49.00.   DO not buy Avast Antivirus software.  You will never get your money back.