Game cannot offer Mobicred and pensioner's discounts although they claim that they do

I wanted to purchase a printer using Mobicred as a pyament option and my Game pensioner's card for the discount. While Game provides facilities for both Mobicred & the Game pensioner's card, it seems it cannot accommodate both at the same time. At the Eastgate Store, I was able to use my Game pensioners card, but cannot pay with Mobicred and online I can pay with Mobicred but cannot use my Game pensioner's card. I don't think this was intended, but no-one I approached could help me.