Overbooked and left us stranded

Booked over the phone with a UK number. Spent night in Cape Town to get this bus rather than intercape which only gets to our destination at 1am. Informed an hour before pick up that bus was full. Called up and they said it was full and because we didn’t pay booking wasn’t secure. This was not informed to me on the phone. When I became upset she hung up on me. Did nothing to help. Worst customer service ever. Now have to hire a car, fly or get the intercape. So disappointed!!!!!!!!