Slow and poor service from Discovery Credit Card

It saddens me to do this, but how many more times must I phone and spend hours on the phone with Discovery Credit Card until my problem will be resolved. I have about R8000 worth of Discovery Miles that I would like to spend. Two weeks before Christmas when I wanted to spend the money, my discovery miles weren’t indicated on my profile. Therefor I could not spend it. I have phoned Discovery Card numerous times, spoken to their card department many times and still the problem is not resolved, 2 weeks later. People tell me that they would phone back but it does not happen. I’m ready to move to a new company but I want the R8000 Discovery Miles that I built up over a long time.