Can buy with mobicredit but NO!

I do love your shops and products bit I don't like todays shopping. I was in Cash Crusaders The Reef to purchase 2 products, when I was at the till to purchase, I told the lady that I want to purchase it and my Mobicredit account. After she rang it up, she told me the amount and waited for the payment. I told her again that I want to purchase it on my Mobicredit account where she then went to speak to the store Manager. After she returned she said the manager said I can't purchase it on Mobicredit. I asked her why because it indicates on your website that we can purchase it via Mobicredit. I did pay with my bankcard, not the way I wanted to. I ask you to answer why you show on you website we can purchase via Mobicredit but the store manager said we can't?