My individual plan was retroactively cancelled even though I’ve been paying my premiums. I think it might be because I was recently diagnosed with a serious health condition. Is this allowed?

No, not if your plan complies with the Affordable Care Act. Under the Affordable Care Act, insurers are not allowed to cancel (or rescind) an individual’s coverage unless that individual commits fraud or intentionally lies on their application for insurance. Further, insurers are no longer allowed to discriminate against any individual because of their health status (however, insurers may cancel coverage if a policyholder fails to pay premiums). If you believe your insurer has cancelled your coverage because of a recent diagnosis or your need for health care services, contact your state Department of Insurance. Note, there are some plans that do not comply with the Affordable Care Act and may cancel your coverage due to a recent diagnosis. See the alternative coverage section for more information. (45 C.F.R. § 147.106).