Beware - Standard Bank's qualifying Credit extension!!!

Standard Bank called me telephonically advising me I qualified for a credit extension. I accepted it understanding there would be NO catch - only to find out last weekend that I am not in R22k debt and every time I use my credit card - for every transaction there is a monthly fee that you can't every pay off - associated to that use. I move money into my credit card every month and have NO idea how I happened to make use of this credit facility . I went to the bank to cancel this immediately and no-one could help me on Saturday. I was given Fabio Panzeri's number but no answer either. Standard Bank PLEASE cancel this facility and to the citizen population out there - be careful what you agree to when they call to advise you that you QUALIFY for a credit extension....! How my own bank can place me in a position of debt is beyond me!!!!!!