Disappointing experience

So I have an Avios credit card which apparently falls under Absa bank. I have been controlling this and ensuring that every month it's paid or sorted out. One month there was no payment but immediately following month I made such a huge payment of R6400 but this bank reduced my limit. Which bank does this without notifying the client. Next thing I call and I don't get any assistance. Emails go unanswered for days. What am I paying for? The consultants are rude and slow. Such a disappointing experience.