The way MWeb operates.

A few months ago I wanted to change my data package. I was told by the sales office that I was not allowed to downgrade and I was transferred to the cancellation office. The person wanted to know why I wanted to cancel and I explained to him that I wanted to downgrade and that I had to first cancel my existing contract. He said that it was not necessary and he did a downgrade for me. No charge, no problem. Yesterday my brother downgraded his package through the salas office. No cost no problem. This morning I phoned the sales office to do a downgrade on my existing contract. I was able to do the downgrade but had to pay in excess of R400.00. So, everytime you phone to do business with MWeb there is some kind of curved ball. Why is that?