The story has some problem, Doubi is not an SSR developer, SSR was a high school girl's popular personal fork who mysteriously stopped.
Doubi is a blogger sharing GFW circumvention tips, like easy-to-use installing scripts for VPS, tutorials, reviews and a list of donated free acounts. Before his arrest, his blog had been under attack, domain names blocked.
The phone number thing is very dangerous, twitter bascially won't allow you to use it after a while if you don't provide a valid phone number.