Ouch.
Another one...
I had this finally resolved last week.
Before calling them, call your number. Make sure it is not someone else's voicemail(I had that fun added to your problem)
Then when calling, hope you get Bongani, that helped me, or one of his co-workers that also listened, in training.
They had 2 voicemails loaded on my account.
There was another problem on their system too..
It took 6 calls and 5 dozing co-worker, before I got helped...