Unfair Treatment

I have a loan in African Bank and i struggled to pay the agreed amount so i called them and arranged for a lesser amount, they agreed and i paid accordingly. On the 15/05/2017 they did not deduct then i went to my bank to enquire and they showed me that African bank did not schedule the debit order to deduct nd i called African bank asked them and they told me that i am the one who stopped the payment and i told them thay i was at my bank and they showed me that you never made an attempt to debit but the lady kept on saying the debit order was cancelled. I then made a new arrangement but to my supprise they did not deduct in November this year. When i went to my bank i was told that there was no attempt to deduct and i made arrangements again but they called me claiming that i have stopped the debit order and i have decided to pay them by making arrangements with my bank and that i working for me but now they have made their arrangements so my money get deducted twice but i managed to reverse it. I don like the way they habdling my account i hope we can find a way to resolve these issues.