Sell-SA Terrible for Sellers

I have been a seller on Sell-SA for quite some time now. Whenever I get an order through their platform, I send it immediately( as its digital). I am always available for any questions from the buyer etc.. HOWEVER.. Sell-SA takes 5-7 WORKING DAYS( and apparently now going on for 8 working days) to pay the seller out the money rightfully owed. That is after they take a huge fee for selling on their site. I have emailed and emailed, and for the most part they either go unanswered, or with the standard reply of - payments are done within 5-7 working days. Now payments are going way over this, and their is now no reply from their side about the delay. Very disappointed in their service to the sellers on their site, considering we are the ones keeping them afloat.