FALSE ADVERTISING

I ordered 15 cases of 300ml coca-cola. When they delivered it, they only delivered 3 boxes and 3 Sixpacks. I show the driver on the invoice that it is wrong and they owe me more, I already pay for it online. He said he would go back and get it. I had to call later to follow up, they keep transferring me and then say they will get back to me. Still waiting, !!!!!!! WHAT NOW!!!