24 month contract become 25

I phoned Cell C to cancel a contract that was signed on 1 February 2016 to cancel on 31 January 2018 just to be informed that the contract only expires on 28 February 2018. The more you try to explain to Dudu Molefe and later Phumla Moratana that 24 months is 24 months and not 25 and all managers are in a meeting. Eventually when they realised that I will not go away a Crean Naidoo the manager spoke to me telling me that he is working there for 13 years and he studied contract law and in all this time time contracts work like this becoming 25 months, Eventually our highly qualified contract expert was not prepared to speak to me any further. Cell C has lost me as a customer finally this is my 3rd contract that I cancel with them and will splash this on social media and everywhere where I can and will also report this to ICASA.