If you were not provided information as to the limitations, that may well have been fraud: a misrepresentation about a material or important fact, done to induce you to do business with them (i.e. buy the coverage). Fraud would provide a basis to do one or both of seek monetary compensation (e.g. the cost of any medical care you get which they do not cover but should have, had the coverage been what they led you to believe) and/or void the agreement and get out of it, so you can buy other insurance. The key is showing that this information was not provided to you at all (and not, for example, that it was there but in the "fine print" which you overlooked, since if provided to you, this was not fraud).