FED UP with KFC extra costs and RUDE staff

Both KFC branches in Kroonstad have rude staff.Staff there shout at customers . We get charged an extra R5 for a buddy coke when THEIR filter machines do no work .We are not allowed to leave the coke sonwe dont get charged more for those meals thag come with a coke. A staff member there has actually verbally threatened to slap me. Assistant managers say its not their problem when the machine does not work. Whose problem is it?