No refund received at all

I wanted to buy power banks for my restaurant for customers to charge their phones while their is loadshedding etc. I received the order after a few days of placing the order online. I decided to open one power bank and charge so i could see how it worked etc. I was very disappointed with the product as it only charged 23 percent of my phone and then the power bank was dead. It said the power bank was 20000mha which i thought this was powerful as the one i have at home is 5000mha and could charge two phones complete. But this was not the case. So i logged a complaint and asked for the products to be returned. I was told i need to send the items back at my own cost and 15% handling fee will be charged. Okay so i sent it to their warehouse. Customer service accepted the products and asked for proof of baking details for them to do the refund. I sent everything through and was told it would take up to 7 working days. I am still waiting for the refund even though the seven working days has long time gone. Nothing as yet and everyday i am trying to contact snatcher etc and no response, phone gets put down etc.