Dell laptop power supply not part of laptop warent

On Sunday I went to Incredible connection in Rosebank Mall to tell them that the power supply that came with the laptop that I bought earlier this year was not working. The laptop is still under warranty. They said that the power supply is not covered by the warranty. I bought a new power supply for R800. I phoned dell to find out if this is true. it is not true and they are going to replace it for me. I have been done out R800 by software connection.