FNB Ebucks reduced reward level for no reason.

I have been receiving Ebucks from FNB for many years and do everything possible to ensure that I receive the rewards applicable eg, purchase form the correct stores, swipe my credit card, fill fuel at the correct places and ensure my investments are with FNB. In August FNB Ebucks reduced my level from 3 to 1 without any warning for no reason whatsoever. They seem to be manipulating the system and clients have to be constantly checking if the correct actions are taking place. This is unacceptable on every level.