poor service and not keep to your promise

i cannot believe the lack of customer service from Vodacom. I wanted to cancel my contract in December- they referred to to the retentions department where they did a price match and offered me additional data on the contract package and to date i have not received what was promised to me!!!! i have called them over 20- they keep saying that they investigating but it so simple as all there calls are recorded!!! i also sent several emails- not even one response!!!! over 2 months since i upgraded and no feedback on what they promised me!!!!!