Disconnection SMS

Please make me understand why did I receive an sms telling me that I will e disconnected if I don't pay. I paid my account on the 27th of January 2016...why does my payment not last 30 days. That is not fair. What makes things even worse is that when I phoned a few months ago to change my billing date. I was told that I have to wait for the 3rd of the month in order to do that...THAT IS NOT FAIR. I can not afford to get charged the disconnection fee again. This has been happening since November...I am tired of it. Change my monthly circle with no additional charge and make sure that I am billed properly. I can't pay an account twice within the space of 30days. If I pay on the 27th then I should be billed on the 27th of the next month....surely!!! If this is not sorted out now then I will take this to the Complaints Commission or the Ombudsman. I cant be complaining about the same problem over and over again...its not fair.