Before ACA, insurance had a more traditional "dump you when you were in need" role that leveraged pre-existing conditions rules by, if you fell ill in a way which was likely to be sufficiently expensive to make this profitable, looking for any minimally tenable evidence of an undisclosed pre-existing condition (just to have something to cite as a pretext, it didn't need to be convincing), using it to justify cancelling your insurance, and avoiding any legal remedy by refunding your entire lifetime of premium payments.

Of course, whether or not you actually had a pre-existing condition when you had signed up for the original insurance, you now have one that prevents you from getting new insurance,