incorrect billing

I have a credit card with standard bank which I owe. I called in so I can settle the amount that I owe. On request if this I was told I will be sent an SMS. I never got the SMS although they insist that they sent it on the 17th of this month, which was the day I called. They called 5 days later to tell me that they are still waiting forthe payment. After informing them that I never got one the lady said I will send another one and hung up onme when i received one the amount reflecting was double the amount I'm suppose to be left with.