Studying abroad; phone blocked

I am doing my doctorate abroad, but still bank in South Africa and have now completed my studies and want to return. I tried to make a payment today, needing my vodacom number to do so. I tried to do this, and it seems that -despite putting on roaming- my account has been deactivated. It is only 6 months today.

I tried to call the call center three times to get it sorted out -from abroad!- and I got kicked off twice because they "didn't recognize my number". So what am I supposed to do? Am I no longer a client just because they decided to delete my number? How am I supposed to get help? And how on earth am I to make this payment?

I really hope I can keep my number, but goodness knows with the way cellular companies are going in South Africa at present...