I noticed before that I can't send an SMS with about R3.50 airtime left. Was with my Samsung Galaxy S. Don't think something like this would be phone related, but rather our sh*tty networks that wont let us use what we paid for so they can con us out of more money.
Then I made a call and was cut off about 3 seconds after I was answered, and left with a few cents of airtime after that 3 second call.
This was a while ago though, maybe 4 or 5 months. Also on Vodacom, and was contacting a Vodacom number.
lol yea well sometimes its quite annoying as im on the top up contract and i see i have R4 left on the last 2 days which i can get by just using whatsapp
but now it doesnt work ;( sigh!!!