Didn't they charge you before? If you had started the trial in 2020 and didn't cancel it, they should have charged you after a month. Have you looked at your old transactions?

Or did you indeed cancel (as stated in the subject of your thread) and just mean you forgot about eBayPlus in general? As you say you are not a member, maybe you did indeed cancel.

I would contact CS via live chat if I were you to clarify the situation.