You can’t count on any one VPN for any length of time in China, the state is engaged in a running game of whack-a-mole with such services so what works one day may not work the next. If you’re planning on using a VPN in China you’re probably best to wait until you get there then ask around for a working service. If you can get over the language barrier it shouldn’t take long to find someone who knows what’s up.
What I’ve found to be 100% reliable across multiple trips to China is to create an SSH tunnel through to a virtual private server that I rent in the US. I guess there are too many legitimate uses for this kind of secure connection for them to be banned on sight, but once you’ve got your tunnel you can run what you like through it. It’s reliable for voice calls and conferences, but video calls are iffy. I’ve found that if you try to transfer too much data (downloading large files or torrents for e.g.) they are liable to rate-limit you down to dialup speeds.
It might be a bit harder to set up than your average consumer VPN, but if you know how to Linux then sshuttle will do all the hard stuff for you. I imagine it’s more expensive for the amount of bandwidth you get than a VPN subscription, although you can get some pretty good deals on a VPS if you shop around. Anything you can SSH to will do the job so if you have a fixed IP address you could even set yourself up with an endpoint at home or at a friend’s place, but dynamic DNS services like No-IP are blocked so unless I’m missing a trick it’s fixed IP or nothing.
If you absolutely must have a dependable hole in the Great Firewall then it’s the best option I’m aware of.