Disappointed with MTN not honouring a contract

The migration department contacted me last Thursday the 28th of January They offered an upgrade to more minutes, 1500 and 8gb data THEY stated it is a contract until 4 July 2021 when my current contract expires and it would become effective within 3 days Well nothing has happened so far and I feel very upset that this new contract, initiated by MTN Migration department (Salome) has not taken effect as was promised I wonder about the integrity of a company if they don't stick to their obligation! JR Olivier ***