over billing than the agreed period

I don't know how many times should I keep complaining about the same thing over and over again.I received my phone on the 29th of April 2013.I started paying for the phone from May 2013.I believe that my last payment was last month being April 2015, but nooo i have rceived an MMS saying that you will deduct R482.50 at month end being May,Now! please help me understand as to why should i pay for 25 months?<br> Regardless of whether my contract starts at June or July the fact is I took the handset in April and started paying in May 2013, can we clarify this ASAP.<br> I would also like to CANCEL this contract as I have had a lot of bad issues because of the *********** admin that you have.<br> Why am I being ********** my hard earned money?<br> <br> I promise that you will not take my money come May 2015, I refuse to pay for 25 months whereas the contract agreement is 24 months<br> Now lets count, I have been paying since<br> May2013<br> June2013<br> July 2013<br> August 2013<br> September 2013<br> October2013<br> November 2013<br> December 2013<br> January 2014<br> February 2014<br> March 2014<br> April 2***NOW that is 12 months, repeat the same pattern and you will<br> end at April2015 which makes up 24months<br> I want this sorted.