Bad service at pick and pay greenstone!

i bought a heater at pick n pay Greenstone mall, i was not happy with the product so i changed it and upgraded (with a few hustles and minimum insults) the one i upgraded to worked for two days and stopped working so i took it back, the ladies at customer service insulated me again! and told me i cannot us a heater and they will get someone who knows how to use a heater to assist i ignored and they tested and found it faulty. they then gave me an old heater which i think was used and has dents and not all the *****s are there. the heater is the same as the one i bought 3 years ago. the one that died was a actually an upgrade but they gave me one that looks like has been used before. I chose not to argue and accept the product and leave after the insults. is this how you treat your clients when products are faulty? are we not allowed to change products when they are faulty? are they taught to insult us and give us dented products without all the *****s? disappointed!!