All ACA-compliant plans must limit out-of-pocket costs to $7,900 for individuals and $15,800 for a family in 2019 for services that are considered part of the essential health benefits and that are obtained in-network. There are a few possible explanations for why you are getting billed for something that puts you above the limit.
First, if you obtained an item or service not considered part of the essential health benefits, or received care out-of-network, your health plan is not required to apply those costs towards the limit on your out-of-pocket costs. Plans can also exclude non-covered services. Also, your deductible and out-of-pocket limit re-set every year, so if you received services that extended into a new plan year (i.e., from December into January), you will be responsible for charges incurred in that new plan year.
Second, it’s possible that your plan is grandfathered/grandmothered or short-term limited duration insurance, a policy through a Health Care Sharing Ministry, or another form of alternative coverage doesn’t have to comply with this rule. See the Alternative Coverage section for more information on types of coverage that do not meet ACA protections.
Finally, if your plan has separately administered benefits, for example, for prescription drug coverage, it can have separate out-of-pocket limits, but the total of all caps combined cannot be more than $7,900 for an individual or $15,800 for a family in 2019. Check the details of your plan to see how the out-of-pocket limit is applied in your coverage. Your Summary of Benefits and Coverage will provide that information. (45 C.F.R. § 147.140).