My friend had a vodafone phone, and could text her mum in Russia, but her mum could not reply to her. I tested on my telecom XT phone, and she could reply to me so she went out and bought herself a prepaid XT mobile.
however on the new phone with new sim (the number is new, it is not ported) her mum cannot reply.
So we both send a text to the same number in Russia, (both on Telecom Xt 3g) her mum receives both messages, she can reply to mine and I receive it, but she cannot reply to my friend. (the Russian phone is on beeline, which states xt can send and receive)
Teleocm support could not help us.