Charged for Out of Bundle Data

While perusing my Vodacom account this month, I noticed an unusually high bill for data usage. I called Vodacom to find out why I was billed for out of bundle data as I always make sure I have data on my phone as soon as I receive a sms from them that my data is low or has run out. As proven on the system I received a sms on 17 March that I ran out of data and then I purchased additional data straight after (according to them it was only 4 hours later but we all know that Vodacom system is a bit slow in updating data). Then according to the system I ran out of data again on 24 March. When I asked them did I receive a notification, I was then told no because it is my responsibility to check my data myself.<br> <br> Now my question is, why offer a service like sending regular sms's informing clients that their data is running low or is now finished if they are going to do this once in a while or when they feel like it. I have chatted to a few people and they all confirmed that they too rely on the sms's they receive. <br> <br> I was also told that I requested for my notifications to be sent to an old number that I haven't used probably for the last 3 - 4 years? I have never requested this?