Hello my name is ***** ***** certified computer professional with over 10 years experience. I will be happy to help you.
I am sorry to tell you that this is not a legit service. They are the ones who put up the webpage that said you had issues with your computer and then you got sent to them. It has nothing to do with microsoft. This company is most likely located in India. What they usually do is lie to you about problems that your computer does not have and then get you to sign up for their support which you do not need.
I would suggest you call them back and cancel. They may not let you though so in that case I suggest you call your bank immediately and tell them what happened and to stop payment.
You can also report them on this website https://www.ic3.gov/default.aspx
If you need further help please let me know. At this time please click the stars above, 3 or more to acknowledge you have received my answer and advice.