Were is my greenbacks????

I have been accumulating my green backs for the past couple of months, with thousands being spend from my American express. The last time I checked I had a couple of tens thousand greenbacks points. When I checked now I only have 58????Water Tango Foxtrot... I did try to phone but with no success. Your website gives nowhere were I can check were my points has gone, nor how does Nedbank come up with the figures they claim I have.. Please contact me regarding this.