KFC - Terrible service from mamamger

Received such tertible service from the manager(Jayson) of KFC (Watetstone Village- Somerset Wrst) - I ordered a Streetwise 5 at the drive-thru and requested that the large chips be replaced by a large coleslaw (which request has been approved many times before) - the employee referred me to the manager, Jayson, who outright reused my request. When I asked why, he started by saying that the packaging differs- when I ask him what the price is of a large chips in comparison to a large coleslaw, he confirmed both is sold for R19-90 ..and still he flatly refused to exchange the large chips with a large coleslaw - at last I had to settle for a small coleslaw - I think what is so upsetting is Jayson's unwillingness to try and accommodate a customer !!