My 24 month contract was increased after 12 months

I first queried, Ref [#***4] then complained, a month ago, about the issue of my 24 month contract being increased from R79 pm to R84 pm, without notification after only 12 months, but have not had the courtesy of a response to either. <br> I tried calling the 808 number - no luck. I am aware of the industrial action which MTN apologise for but they still seem to be able to send all the sms's with special offers telling me I could win R5000 or even a house worth R2mil. If they afford to give away all this money and houses why has my contract increased? Furthermore the July 2015 issue of Y'ello deals offers my phone ,Nokia Asha 503 at only R69 pm, so how is it justified that my deal has increased. Am I, the current Valued customer, sponsoring the potential new customers and the houses being offered as prizes?<br> I am a pensioner and went for the most cost effective deal at the time, I don't need an increase in call value, I was quite happy with my R79 deal. If I had been advised of this increase I would have queried it at the time. I fail to understand how a signed contract for R79 for 24 months can just be summarily increased without notification after only 12 months.<br>