Worst service at Sammy Marks Square cash crusaders and a rude manager

I bought an inverter at Pretoria Sammy Marks Square which worked for 3 days,after that it was no longer charging and took it back,the manger who is a white lady who said I left it plugged during load shedding ,they cant refund or exchange it to me is the risk I took when I bought a second hand thing.I had to shout for me to get the attenton,she just didnt care.She was very rude and even refused to give me her name.The whole store refused to give out her name,even the white guy there.She said I must send head office and email,she is very confident that I will not get my money or fix the thing.If you value your money ,dont use this store.