I'd be curious if OP could chime in about that, since the service they posted claims they don't need you permission if you aren't on the Do Not Call list [0]
> Note: They don’t need your permission if you haven’t put your mobile number on the Federal Do Not Call list, but don’t worry, if you haven’t we tell you how to do that too!
> Note: They don’t need your permission if you haven’t put your mobile number on the Federal Do Not Call list, but don’t worry, if you haven’t we tell you how to do that too!
[0] https://www.isipp.com/how-to-make-phone-and-sms-spammers-pay...