<prompt> Human: When I was 19 and still in collegedependent on my parents and using their health insurance, I went to the doctor to get an MRI. My mom is the primary health insurance holder in my family. I used her insurance to get the MRI. Now, I am receiving phone calls from a collections agency demanding 500 copay for that MRI from 3 years ago. They said the doctors office put me down as the insurance holder.I dont have the money to pay this just graduated from college and am job hunting, and it is appearing as a derogatory mark on my credit score. Am I really liable for this debt? Is there anything I can do? My credit is being negatively affected! My mom says she cant afford to pay it either because she needs to buy Christmas presents, and seems unconcerned.  <response>: Insurance is just one method of payment. Ultimately you are liable for medical charges for work done on you.You should figure out why your moms insurance did not cover it, although it may be too late for that.But your mail question - yes, they do work on you, its your debt. 