Extremely Poor custome service

On the 08/05/15 i called MNT CC to enq why my acc had not been debited the end of Apr and was told that debit order instruction was sent to my bank,but nothing happend.I was told by the that he will arrange for a once off debit for 11/05/15(***),but nothing happend.I called in again(12/05/15) n was then asked to confirm my banking details which I done,only to discover that someone changed my bank details without my approval and for some reason the agent could not tell me who changed it n y.she then updated my bank details and assured(***)me that before then end of the day my acc will be debited.to my \suprise"nothing was done.I called again today(13/05/15) and spoke with Nteboheng Moloi n had to explain myself again for the third time and again was asked to confirm my bank details and at this point I became irate but was not rude.She could not give me a reason as to why my acc was not debited"