Samsung R500 Accessory Voucher Dishonesty

I have recently upgraded my contract with MTN to a package offering a Samsung Galaxy S9 with a R500 voucher for "selected original Samsung accessories". I have since been informed that "selected original Samsung accessories" as stated on the voucher actually means "phone cover only". The disappointing thing is that the phone itself comes with a cover in the box. Why would I need a second cover for a single phone? Most of the covers are also well in excess of R500, which means that I would need to pay the difference for a product I do not even need. I find this dishonest and a marketing exercise purely for the sake of marketing, and is not at all in the interest of the customer. I am therefore reconsidering my loyalty to Samsung products because of it.