coca cola don't allow Eft. Why??

As a Retailer I find it very difficult and upsetting working with coca cola, You order their products, come delivery day, flash machine is offline and they don't allow EFT payments. Flash machines don't work when there's load shedding. You call them to arrange alternative payment method but then you are threatened and told they will stop supplying u with their products. they tell their driver to come back with their stock, R50 000 stock after their guys spent 3 hours offloading. Why should a big company like coca cola only accept payment from flash?