Empty promises - Woolworths

I don't know what to do anymore. Every time I buy something online with my Woolworths card it blocks it. It says that my sequence number is incorrect but it is not. I then have to phone Woolworths to get the car unblocked. This has not happened 4 times in the last month and everytime I need to phone you guys. You then promise me that IT will look at it and fix it, get back to me but no one ever does. Now it is blocked again!!! I e-mail you and you said I should phone you back. Why should I phone every time for something that is clearly a problem on your side??? I am tired of promises after 1 month. Can you please phone me and get this fixed as I can never buy anything anymore.