Dating Website Support Forum - Webscribble

Hi paul,
thanks for contacting me on scriptlance regarding custom work. I posted an ad for help with adding sms phone verification to webdate. I have a problem with a spammer that keeps signing up for multiple accts . He uses all different u.s. proxies so i haven't been able to stop him yet. He pays for a membership through paypal and then spams people and then cancels his paypal payment. I have yet to stop this guy. I saw that many of the large sites like facebook and now craigslist are now using sms phone verification. That way you can only open one acct with a cell phone number. If the person spams then i can block his cell number and he won't be able to open a new acct with the same number. How hard would this be to customize on my website? I would like people to verify their cell phone number after they pay for a membership and before they can send out messages. Thanks for your input.
Jenny