How to sign up for a Weixin account?

I need to ask questions to developpers of Chineese software (200000 different users but not well known outside borders).
And of course, the rule is no email, no GitHub, no Stack Exchange, but Weixin QR codes on the project s website which by the way isn t translated.

I read that in order to talk to mainland Chineese users, I need Weixin as WeChat is a version preventing to talk to mainland.

The problem is I don t know any Chineese user, and as I don t live in Asia, I ve no idea on how to get a Chineese mobile phone number (even temporary).