Untimely roaming switched off

I switched my roaming on before leaving South Africa, with my phone still being on contract as I could not cancel the contract without additional fees or payments. After the final contract payment I notified Vodacom that I want to switch my phone to a top-up/prepaid system. As the system was app****, roaming was switched off for some unexplained reason. Can @Vodacom please confirm why this happened and assist to resolve this matter?