Please Help: I used a marketplace plan for a year that I just found out I probably wasn’t eligible for, what will happen?

So I applied for the marketplace last years when I turned 26 because I was under the impression that I was not eligible for health insurance through my employer because I was part time and from what I was reading online you had to work a certain amount of hours to get that. Apparently that is not the case and everyone was eligible regardless of the hours it was just a super limited (not full comprehensive health insurance) plan. Before re enrollment this year I called my workplace benefits center to clarify that I wasn’t eligible and the guy said no I wasn’t. But then I got a message saying I was because I was part time.

After looking at the benefits website through my employer for something completely different I realized I may have misread the website, so I called them again and asked if I was eligible and he said I was… I asked if that was based on hours or just because I was part time and he said it was for all part time people.

So based on my (incorrect) understanding of the policy I answered the question asking if my employer offers insurance incorrectly last year and at the start of this year…. I barely used the health insurance plan except to pick up birth control twice at a pharmacy. Does anyone know what is going to happen? I genuinely didn’t know but I don’t think the government would let me use that as an excuse.