Why can't Vodacom call me back?

Called Vodacom on 10 November to advise that I would be unable to pay my full phone bill at the end of the month and would it be possible to make arrangements. The agent told me to cancel my debit order, which she did there and then and to make a manual payment of what I could afford, which I did on 26 November. I got a sms today saying I have to deposit more money or phone to make arrangements which I duly did. Talking to the agent, explaining all and then silence, the call disconnected. I had to call Nedbank thereafter for another issue, same thing happened and Nedbank phoned me straight back. Why can't Vodacom do this???