Vodacom false contracts

Been with vodacom for over 20 years, Last December I renewed our business contracts with them, Their deal wasn't so good so saw an ad from mtn which was excellent, decided to switch as went into the vodacom store and showed them the mtn ad and they said they will better the deal if we stay with them, they did a deal match and all was fine until 6 months ago, When they reduced the minutes and data by half, Since then been speaking to the person at vodacom who sold me the deal and says she spoke to management and head office and they not willing to assist in any way now, The deal was for 24 months now they gone back on their word... Absolutely disgusting from them I will move over as soon as I am able to stuff vodacom who don't value their word nor the longtime customers