From how they’re presenting themselves on their website, I would also guess their payment methods aren’t private /anonymous at all. It seems like you could even be forced to use the Apple/Google integration to pay for your subscription (which just means you can’t really pay privately).

Also, VPNs that have own apps and don’t allow access via OpenVPN are a red flag. You don’t know what their apps are doing and they don’t give you any reason to trust them either.