Never previously being eligible for an HSA, I switched to a new health care plan with an HSA effective at the start of 2019. I made a couple of contributions at the beginning of the year. Some time recently, long after taxes were filed (where I didn't report any 2018 contributions since I didn't intentionally make any), I noticed that one of the contributions I made somehow went to tax year 2018. There's no way I would have intentionally made a contribution to the previous year (where I wasn't HSA eligible), and I'm surprised the provider even allowed it to happen.
Moving forward, I realize that there may be a tax penalty, and I'm wondering what I need to do in order to correct or minimize the situation.
Do I need to:
Take any action immediately? Can I do anything to revert it or is it too late?
Report it when filing 2019 taxes
Edit: I called the HSA's support line. They said it should show up as resolved by the end of the week. I'll edit this again if it works out.