mac airbook hijacked

I was configuring an epson printer I had just purchased and wrote in the search bar epson.com thinking I could find where to download drivers, but to my surprise all of a sudden a popup saying your computer has been blocked call apple support for assistance I called and rapidly noticed the tech had an indian accent and heard other people in the back ground speaking Indian also it came to my mind this was the scam where they hijack your computer to ask for money the computer was sounding some loud tone which made hearing the scammer difficult so he had me press certain keys to turn the noise off so far so good then he asked me to write in the search bar a certain url address I told him I could not, that my screen was frozen and had no control over mouse or track pad once he unfroze my mac and I regained access I turned my wifi off and hung up, in the afternoon I activated my wifi and downloaded and paid for a antivirus with ransomware protection. So far for my belief that macs were un hackable. Beware never say never keep your mac safe a good antivirus is always welcome.