Bad service of uninformed staff and management

I bought a Dixon mouse and keyboard at the Promenade branch but we discovered there was no sensor. I went back on the 26 December to buy a new sensor because it was 6 months ago and i was told by one of the staff members to bring back the slip because they do not sell the sensor seperately and the sensor was supposed to be in the mouse. I went back on the 27 of December with the slip just to be told its way too long and tgey cannot assist me. I told the lady that came to assist me that what am i suppose to do with the key board nd mouse because i wont be able to use it. She told me there's nothing she can do because it's too long ago. I told you give me no option to post you on Help Peter and she told me you can go ahead. I am disgusted in the service firstly i bought something that i wont be able to use ever with a slip as proof that its a Cash Crusaders brand and secondly i wasted my time and petrol to go back for nothing.