Making me pay for their mistakes

As a client of Afrihost already I thought i would purchase the monthly mobile plan and waited a week to follow up about my deliver date. When I contacted them they said to me that they did not even process the sim, but I was already charged for the sim and minutes for the month. The courier company contacted me the following week and could only get the sim to me by weeks end (making it 2 weeks since purchase date). When i tried cancelling the order they would only pay back for the minutes and not the actual delivery costs. I don't feel its fair charging me for a mistake made from their side, but whats worse is I complained and keep getting a different answer from a different person. How am I supposed to resolve a issue if they keep replying with the same answer.

Needless to say I'm moving my business else where. This isn't the first issue I have had with them.