I would not trust the website. Any effort to have nuisance callers or websites associated with them put you on their do-not-call list will only confirm that your phone number is a working one and the odds are good that they will sell it. I have found the only thing that helps to reduce nuisance calls is to ignore all of them and never in any way to respond to a caller who does not leave a personal relevant message. The government's do-not-call registry is useless (it probably isn't funded to do anything beyond maintaining a website and an office somewhere to create the appearance of a working department) and ultimately this problem of unwanted phone calls is simply one of the unpleasant aspects of modern life.
I get calls from this number 2-3 times a day for the past couple of months..I never answer numbers I do not recognize..I let the answering machine get them..They never leave a message. So, I know their telemarketers or scams.