Told to return food but they don't refund your money

I purchased an order via the App and it was not accepted or completed. I then repurchased and both orders were placed and deducted. I called the branch to inform them and they said I should return the one order when the driver arrives. I did exactly that, when they received the other meal they called to let me know that my money will be returned within 2 to 3 working days. It's been 16 working days, i have sent an email on the 7th January to customer service and still no reply. This is not a oh you got my order wrong, this is you owe me money and repay it.