Worst customer service IN THE WORLD!!

Received my order damaged and not in a working condition, sent it back exactly as is. I asked for a refund and they said they will give me a refund in 14 working days they will just need to subtract a repacking fee of R170 (for bubble wrap) I agreed. It has now been 18 days and they sent a mail now saying they will need to charge an extra R180 for courier fees(knowing they sent me a damaged product) and R400 because they didn't receive a charger. Why did they not communicate this after receiving back the package and done the assessment, because they are grasping at straws.