I can never use my credit card at a merchant

Every time I use my credit card at a merchant the transaction will not go through. I can draw money from an ATM and that is it. Every time I try and log on to internet banking relating to my credit card it is blocked after one attempt. I have phoned Absa Credit Card division a number of times and it has been supposedly unblocked when I try use it again it is blocked. I went into the bank at lunchtime today and they reset my pin, I came back to the office and tried to log on to internet banking - guess what blocked again. I phoned Credit Card Division and I was told to go into the branch AGAIN - NO I am not and neither am I emailing technical to tell them what my problem is why doesn't credit card division do that? For goodness sake sort my problem out once and for all so that I can use my credit card or else what is the point in having one! I bank with Nedbank and FNB and never have any problems like this, I can use my cards anywhere and I can do internet banking with no problems at all.