Shocked at what I was charged for delivery.

I'm really disappointed with the andiccio greenstone branch. I stopped there earlier and saw that cars where parked outside. Asked them if it's possible to deliever to my house as they offer delivery as a service. They stated that they do offer free delivery within 5kms from the store. My house is 5.4kms from the store and I was charged R60 delivery???? How is this justifiable. R60 will fill the tank of the bike they are using. How can I be charged R60 for an extra 400m.