Is fastsupport.com a scam

I would suggest using the free Gas Mask application to make it easy to edit your hosts file. You can add a new line with a 0.0.0.0 and a tab and then the offending domain and hit return and then save button. This will redirect any calls from that website to nothingness and at best you will get a pop-up window with a can't access this website but it can be easily closed. I have hundreds of nasty domains blocked this way on my Mac. In fact there is a website that maintains a list of over 30,000 such domains worthy of being blocked, but referencing this list in Gas Mask would likely slow down your web browsing as every link would get checked against this list. So safe but slow.

Yes.

Google the company name: one scam report after another in the search results.