1955, CoMantra is a company and they state that they are Microsoft Certified and offer a service to maintain PC's. However, ther is quite bit of debate as to whether they are genuine or not. Certainly they have some dubious business methods at best, ringing people up out of the blue and with no indication how they got your number.
So, please take the good advice you have been given. Do not connect your PC to the internet until it has been checked out and any possible malware removed as ChuckFickens has said. Make sure that you instruct your credit card company not to make any payments, and check what will happen if a demand for payment comes through from CoMantra. Just because ti hasn't been taken yet, doesn't mean they won't try. They may try and argue that you have a contract with them, so be ready to deal with that.
McAfee Site Advisor has the following comments posted:
Rating: Phishing or other scams
Unsolicited "technical-support" call to fix reported problems with my PC - of which I was unaware. Said his name was Roger, but his strong Indian accent made him difficult to understand. Was unable to identify which PC was reporting the error, nor was able to provide satifactory explanation of how he obtained my phone number. Google reveals many similar experiences, in some cases, people were persuaded to part with a lot of money. Seems like it's a scam!
Posted at 28/01/10-05:14:47 by Romney_YW, Reviewer , View profile [ Reputation score: 1 / 9 ]
Rating: Phishing or other scams
This company cold calls implying that they are service providers for Microsoft support. They then try to get you to allow remote access to your PC to supposedly fix errors reported to Microsoft, and also try to sell you a warranty - using very hard-sell techniques