PLease help me... I do not know what to do

I have a 14 year old daughter. She lives in NC with her mother and I live in FL. I have court ordered visitation of one weekend a month and 3 weeks during the summer. I do and have always paid my child support of $665 per month and have no problem doing this.
Now my daughter has decided she is much too busy to come visit me this summer. I have tried to be flexible with dates even with the amount of time. I have even offered to only do a long weekend instead of a full 3 weeks at once. But she basically refuses to come stating she has softball, volleyball, a beach trip, you name it going on.
Her mother is refusing to help in this situation stating if my daughter does not wanto to go she doesn’t have to and no one can make her. Her mother also stated that she has the choice at age 12 over whether or not she goes. She stated no law enforcement will force her to come because she is over 12.
Is this true? What do I do if they continue this? I hate to force her to come but I want to spend time with my daughter. I understand she is a teenager and has al ot of other things going on but I also believe it is in her best interest to spend time with both parents and her half sister. The mother keeps telling me I should just take off and come up there but I cannot afford to. If I do not work, I do not get paid and then there is no money to pay my child support for the week. What are my choices here and does my 14 year old daughter have the right to decide what she does? Can she be made to come? What should I do?

File a Contempt of Court/show cause suit.