Credit card fraud

In WI, I used my dad's credit cards w/o his permission. I ran up about $3,000 on merchandise and travel. I did have power of attorney on his bank accounts, but not on his credit cards. He discovered what I did about 6 months later. When he originally found out, he agreed to allow me to make monthly payments until it is paid off. I made three monthly payments and he has now decided to contest the charges with the credit card company and have the charges removed from his bills. The credit card company said that he must be willing to prosecute if he contests the charges. What am I facin