Trouble Adding Minutes And Reactivating Android Zte Merit

I bought my android zte merit straighttalk phone from walmart on september 17th. Which means my time to add more minutes was by ocotber 17th. today is the 18th. Last night I remembered and added them BEFORE midnght. I entered the service pin, and the operator said that my balance had been updated and told me to turn my phone off and back on again. I did so and fell asleep. I woke up to no text messages which is odd. I tried to make a call and it said that my phone had been deactivated! I freaked out. I called the number to add minutes and pressed 1 to reactivate, and i entered the same service pin. It told me that that pin number had already been used. NO WAY! I just added minutes with that pin and they said it was fine! I dont have a job and i bought the phone and two 45$ minute cards with my last paycheck. I cant find a service phone number to ask for help. SOMEONE PLEASE HELP ME! I NEED MYP PHONE!     Maryanne