For me the same. I have found Revolut service not much usefull for me because of lack 3d secure. Either I don’t use their currency converter feature because it is impossible to topup Revolut card in my native currency. That means should buy EUR or USD and send it to Revolut which is also means double conversiotons.
I started in the beginning of December 2017, and tried to talk with Support yesterday. The agent said same thing. I cannot cancel premium subscription untill Dec 2018.So I have to pay minimum 10 month more for the useless service. I pointed that guy to the official T&C https://www.revolut.com/pl/terms?lang=en that there is no any mentions of so-called 12 December rules, he said i should read the FAQ for such info.
Generally I’m mostly disappointing with Revolut service, both technologically and customer support. Seems to be a scam. They push you to start Premium which you would have to battle with them to cancel it in case of lacking the service.