I wouldn't call it a VPN, it's just an app that uses the existing Tor network, which runs on nodes paid for by volunteers (and intelligence agencies, and data tracking companies....).
They are calling it VPN, I am just a messenger, so you can send them your complains 
I tried testing Tor VPN in my emulator but for some reason it was not working correctly, so I can't give any real feedback, but better usse this app at your own risk.