I can see 2 scenarios happening here –

1) They just didn’t get the info. When you sent it in, did you include something referencing you as a dependent on your mom’s policy? If the document only had your name on it, they may not have been able to identify what policy it went with and thus weren’t able to process it correctly. (Note to everyone – include the policy ID number and the name of the insured individual on ANY documents you send to your insurance company. It will be extremely helpful in making sure your document is processed correctly.)

2) Is the school you’re attending accredited? Sometimes there’s a clause that you have to be attending an accredited university, so if a person were attending a technical school, beauty school, etc. full time it wouldn’t count.

I suspect in your case that #1 occurred, and you should be able to get this resolved on Monday.

Also, you can make the call yourself – anyone on a medical policy can make calls and discuss their own information, it doesn’t only have to be the cardholder. (Sure, if you had never been on the policy at all, your mom would have to make the call. But you can call to discuss your own personal information, which includes full time student documentation.)