Shocking customer service

On 24th December I purchased an underwater light from The Lighting Warehouse in Water glen Pretoria. I asked for a low wattage LED light bulb to suit the high quality light. When I fitted the light bulb it cracked because it was the incorrect length. I rushed back to exchange it but the shop was closed. Today I returned to the shop and was told that they did not stock the correct bulb. I asked what they were going to do about it and they said they did not know. I expressed concern and they called the manager who confirmed that they did not stock the correct bulbs and I made the point that they as the experts sold me both the lamp and the bulb to match. Again the manager said there was nothing they could do. I became angry and because I did not have the slip they refused to refund or replace the incorrectly supp**** bulb. I left the shop in disgust and told them to keep the incorrect parts since they were not prepared to do what was fair and correct. They are unprofessional and clearly ***********.