Problems sending SMS to South Africa (Amman)

Hi all. Has anyone experienced problems sending SMS (text messages) to South Africa? I am with Zain and when I send SMS's to South Africa, the messages aren't received in SA. My cost of the SMS is deducted from my account - but nothing gets through on the other side. It happens with all SA numbers and not just those from a particular network. When I lived in Jordan previously, I was able to send SMS from Orange. I've reported the problem to Zain, but they say that the problem doesn't come from their side.