Debitorder/Stop order not moved as asked

I phoned the collections centre a few weeks ago and told them to move my debit order from the 20th of each month to the end of the move. Needless to say, it did not happen. I phoned in yesterday and explained my situation to Tandile and she promised to get either Natalie or Kim to phone me back. This also did not happen. Very bad service! Please phone me back