Altering My Purchasing Pattern

This week I discovered the reason for a puzzle I was having with a credit card I owned where a catalogue company was charging me for overpaying their bill. I kept overpaying so that they would stop sending me bills saying I owed them when it was, I have lately discovered, their policy to charge for the "inconvenience" of this. Charging me for having a credit? This is legal? Today I returned an item on the same credit card. I was only given a credit by the retail outlet. I began to worry that this company would penalize me for this too and I decided I wanted my money back. I phoned them and they told me that the credit was not showing up on their screens and to try again in 5 days. I will. I have decided I am not buying from this famous chain any more. I am altering my purchasing pattern. I have cancelled all my catalogues. I am sure there must be many shoppers out there coming to the same conclusion. It more than a matter of principle. Do I not want transactions that are straight forward without delays and hidden charges?