Double debit orders for 3 months in a row.

I missed a payment on my personal loan with Standard Bank in January, I phoned Standard bank on the 30th of January to make arrangements to pay the amount that's in arrears over two additional payments by end of February and end of March. My salary came into my account the 22nd of February and immediately a debit order is taken off of my account for the loan, on the 23rd if February I made the additional payment as agreed. But the 26th of February standard bank tries to debit the full amount again. Beginning of March standard bank phones me to tell me I'm in arrears on my account, I tell the consultant I am aware of this and made arrangements to pay the two additional payments. The consultant advised me that I am still in arrears by the full instalment amount. After telling the consultant that it is not possible because I paid the additional payment as agreed the consultant picks my payment up on their system and agrees that I only have to pay the other half of my instalment end of March and that I am in fact not in arrears by a full instalment but only half a instalment. 23rd of March my salary goes into my account and standard bank debits the full instalment, that same day I paid the last additional instalment as agreed. Again on the 26th of March standard bank tries to debit another full instalment. Beginning of April I get a call from them again saying I'm in arrears by a full installment to which I disagreed saying I paid 2 additional installments and they pick it up on their system. All is well I've caught up with my arrears except there is R80 outstanding to which I agreed to pay this month, I asked the consultant to please make sure that they don't try take 2 full instalments again. But to my surprise my salary comes into my account today and standard bank takes the full instalment and they tell me there's another debit order scheduled for the 26th of April for a full instalment as well as the R80 odd arrears. I tell the consultant that it is not what was agreed and they can't take another full instalment if I'm only in arrears by R80. The consultant advises me that I have to go into the branch to request my two additional payments be refunded to me? So I'm asking why did I bother making arrangements if I must now go back to ask for a refund on my additional payments? This is unacceptable. I asked that the debit order scheduled for the 26th be cancelled to which they refused. I don't see the point in making the arrangements if I must go ask for my money back? This is why I left standard bank and went to FNB. Standard bank are absolutely useless and refuse to help you when it's a flaw in their system.