a question for help

hi,

    a question for help: i got a card from the store at market place mall, the staff told me that i could activate it. before that, I had asked for a package of $100 for 1000 minutes call time. but when i actived the card after the staff's guidance, i got a package of $25 per month for 300 minutes call time, wireless. that's not the package i want. so how can i do the change the package to the plan of $100 for 1000 minutes call time? thank you, i want to prompt reply, you know, i'm a new comer and i want to contact with  my relatives in China.

   all the best,

  ruzhuang