NO ONE KNOWS HOW TO HELP

i have a loan, it is set to pay for two months. my first debit order was supposed to go off on the 01/12/2015. however i wanted to pay THAT DEBIT ORDER FASTER. so i spoke to a consultant who said i can pay it & NO DEBIT ORDER WOULD GO OFF ON THE 01/12/2015. i manually paid that installment. now i get a message saying that i will debited on the 01/12/2015 for the difference. THAT AMOUNT SHOULD ONLY COME OFF ON THE 01/01/2016 AS PER THE AGREEMENT. the amount that i paid is showing & allocated. I WANT THE DEBIT ORDER FOR THE 01/12/2015 CANCELLED IMMEDIATELY AS I ALREADY PAID IT!!!!!!. i have been trying since 8am today to sort this out & guess what STILL NO LUCK. TRAIN YOUR STAFF!!!!! Im horrified that its not easy to cancel a debit order because a manual payment has been received.