Victim of a Fake Anti-Virus Software Scam Shares Her Story

This happened to me. It all seemed very legitimate at the time and the "tech" was very polite and helpful.
He assured me this was through MICROSOFT and that my computer had been infected with malware and he was very concerned about the safety status of my data.
I allowed him access to my computer to "remove" the malicious programs and viruses and was given several contact names, ID numbers, case numbers, a supervisor's name and number etc. also given an email address to contact them if problems or questions. I paid 239.00 dollars for the "service".
My computer was working better, was faster, etc. after this episode which is what I was promised.
I received a follow-up call twice asking if I was satisfied. Months later I received a phone call stating the company was going out of business and they needed to refund my money, which involved gaining access to my bank account.
I told the man I had read several articles from the Better Business Bureau stating this was a scam. He then became very intimidating, demanding that I cooperate, etc. I hung up on him and he proceeded to call me six more times. He was menacing and threatening to me on the phone. He said he would crash my computer which is exactly what happened.
I had to take my computer to an expert to have it wiped clean, changed my credit card account and bank account, all my passwords etc.
It was a NIGHTMARE. This all happened last fall and in the last week I have received two more phone calls stating there is a problem with my computer. I practically shouted into the phone for them to stop calling me as I was already scammed by them. Will see now if the phone calls stop.
Who are these terrorists, and why do they think it is ok to do this? I almost had a nervous breakdown over the whole thing and had to get the courage to tell my husband I had been duped.
I am so very careful now, and trust NO ONE. oh, by the way...the emails I sent to them were "undeliverable". Big surprise...scam artists...shame on them.