Change of banking details not done in time.

I called *** on the 16/03/2015 and spoke to the above mentioned agent to change my banking details. The only things I want to change were the account type and the account number as I am still using the same bank. I passed the authentication process and gave out my new banking details. The lady promised me that it will be changed and they will start debiting end of March 2015. Till date I haven't received any notification about my Avbob debit order so I decided to call *** again today. I spoke to Nape who confirmed that my payment was unsuccessful. I honestly got upset then I asked him how is that possible because you have my new banking details and Lizelle promised me that you will start debiting from my new account end of March. He said \there was a delay on their side in the process of changing my details". Who's fault is that? Mine? Well if my banking details were not going to be changed on time and I was informed I would have simply made a manual payment for the month of March like I did with my insurance. I am not happy with the service I received and quite disappointed actually. I would like to know the solution to this problem."""