No refunds on airtime

Last week I had purchased R200 Telkom airtime from the Umhlanga Crescent branch. The cashier had not specified for landline or for mobile. She had just asked me if it was prepaid, which to most people means prepaid airtime for a mobile device. When I had tried loading the airtime, it turns out the airtime was for a landline. I called the manager who then said they don't refund airtime but I can come into the store and they will see what they can do to help. When I went to the store they were highly unhelpful and just told me that they don't do refunds on airtime. Now I am sitting with a R200 prepaid Telkom landline voucher and had to spend another R200 of my money to get the mobile airtime. Since when don't people do refunds on airtime?? If it was a small amount I'd understand