GOLDS GYM CONTRACT WITH A MINOR HENDERSON Nevada

I am looking to see how to handle this situation that I believe is a ripoff. My daughter at the time was 16 when

her dad helped her  to become a member at the Gold's Gym. The amount is $20.00 a month as you go.

My daughter went for about 3 months and it was automatically taken out of my husbands checking account.

My daughter after 4 months stopped going because of school she called and went in person to tell them that she

will no longer be using their services. Now my daughter is 18 and she keeps getting calls from a collection agency

for Gold's Gym... constantly harassing her about her credit and she won't be able to buy a house or get a credit

card. And now its up to $300.00. I call them and they were extremely rude. I explained all  the above

information and they don't seem to care. I told them to call her dad he was the one who original signed 

and tried to give them his number but they said no because she is 18?  Help!!!