This why I stopped subscribing and always buy a one-time code. The price is the same, but I never have to worry about unwanted renewals.
By the way, I have found BMT Micro to be very helpful is straightening out this kind of issue. Yes, it is a shame that the 3DX Devs don't know what they are doing. But fortunately for them, BMT Micro picks up a lot of their slack.