VPN Auto Subscription that I can't cancel

HI There, Unlimited VPN 'Keep Solid' was a free trial which I logged onto and then cancelled a month ago, they've logged back onto my Mac and re-subscribed me saying that I hadn't cancelled auto subscribe, however I wasn't ever given the option. I tried to cancel and delete the account which seems to haver worked and been in touch with their support. who nw say I don't have a recognised account so they can't help me. .. how do I end this subscription?