I have an account with them that I'm paying R159 per month

I have an account with them that I'm paying R159 per month.I am in errears of 2 months after I updated my banking details both on their app and someone that called me but they did not debit and I ended up paying the via EFT R180 trying to cover the arrears.Last month a lady called me and I gave her my banking details again,I asked her to debit R180 then I will pay extra R150 for the arrears.I asked her to send me proof and reference of our arrangement.She didn't only to be debited R881 which was returned due Insufficient funds because I left only the money they were supposed to debit.Now I'm charged R115 for that returned debit order by my bank.