Workplace Won't Give Me My Benefits

I turned 19 in April and was taken off my mom's health insurance. I told my employers when it happened and they told me that I couldn only sign up for their insurance during January and June during their enrollment period. Since the beginning of June, I have been trying to enroll, but everytime I asked my boss for the paperwork he would dodge and say that he would get it later. I still don't have coverage.
I recently had an injury (not job related) that required medical attention that I cannot afford. My dad says that since my employers wouldn't let me sign up for the insurance that I qualify for as a full-time employee, they should have to pay my medical bills. Is this true? Is there anything I can do?

I really appreciate any advice. I have no idea what to do.

sorry i posted this in the wrong section

[annjd]

If they had promised coverage and then caused it to be that you could not sign up, they can be held liable It happens often.