First, you do not need a VPN to play p99 in China. I connect directly without any problem (that is, p99 is not blocked by the Chinese firewall). Note that recently there have been a lot of network issues, but that hasn't been the case for the past several years, and it's not specific to connections from China.
Rogean is aware of this, so hopefully it will be fixed.
Sometimes using a VPN helps, and other times it makes it worse -- most often worse. In any case, I wouldn't ever use a VPN service. If you're good with computers, install your own OpenVPN instance instead.
As for phone number, like others said, you don't need one to play the game. But if you want to use a phone number, a simple solution is to get a Google Voice number and have it forward to your Chinese number. You can use your Google Voice number in all sorts of places, like the credit card fraud check when your bank thinks there's suspicious activity, etc. Skype phone number works too.