Embarrassing situation when using card

I have had a Markham account for many years and have a good payment history. I have recently been in very embarrassing situations when wanting to use my card. I used in card in April this year for a fairly big purchase of ? R4000.00. The available credit was R9000.00 at the time. I have since made three payments of the required amount and every time when I want to use the card, I am informed by staff that there is a minimum payment required. How is this possible on an account which is up to date and have a significant credit available. Markham must put more effort into updating their records and treat customers with a good record better.<br> <br>