I'm not happy with the service and I want my money back

I'm unhappy with the service I got from cash crusaders at Albertina Sisulu. I bought a PS3 remote controller on the 3rd of April I wasn't told that I should test the item to see if it's in good working condition before I leave the store they didn't even specify the specific date to bring it back if I experience a problem with it. I went back on the 11th of April telling them the controller is malfunctioning they told me it can't be exchanged cause I have passed my 48 hours to bring it back and the person who was helping me signed to show that it was tested and they can't help me cause that person resigned. I'm not happy cause they sold me a broken controller and refuse to take responsibility for their employees who failed to test the remote in my presence to see if it's working or not and it's not their problem that they sold it to me in that condition.