Not receiving texts from South Africa (I'm in the UK)
I use a iPhone 4s in the UK; my mother lives in South Africa. I can send her text messages that she receives immediately, but I never receive her response. To the best of my knowledge, mine is the only Virgin mobile she texts in the UK - all of her texts to other UK-based mobiles work fine...
Re: Not receiving texts from South Africa (I'm in the UK)
Welcome to the community and thanks for posting. So sorry to hear you're not able to receive text message from your mother in South Africa.
I've had a quick look on Apple Support Communities and found this post. I have no idea if that suggestion will work and any tests you do would be at your own risk. I suspect it has something to do with an iOS update. Have you updated to the latest one?
My second guess would be to say it could be to do with the way your number is stored in her handset. We use EE's infrastructure so does she have trouble sending to numbers on this network?