Installment Plan keep getting canceled and refunded back to my credit card

i am having a big issue with my installment plan being paid off i paid 365.49 dollars the first time and it got canceled because i thought it was a bill payment then 2 days later the money got put back to my account on my creditcard  next day which is today december 6 2015 it got canceled by att because i was recuesting to remove my  old canceled payment history and i dont know how this agent mis understand me and decided just to cancel my installment plan payment and give me the money back ? is at&t not willing to accept my payment that i agreed to pay if any att Executives or ceo reading this please change your policy installment plan should never be refunded back i agreed to pay 365.49 for my ipad mini cellular +wifi i dont want to keep submitting payment to you i want this payment to be cleared so please change your policy and if any att management or staff can cancel this error please private message me and i will give you the information that is needed i was t old i need to wait 3 days for the refund and i want this fixed please it so frustrating to have my payment keep getting canceled and refunded back to me