Vodacom Kolonnade incompatance

i went to kolonnade Vodacom to reduce my account the sales man talked me into a upgrade but what was proposed did not happen i ended up paying more now the shop owner wont admit they gave me the wrong information when i did the upgrade and customer care say's they cant help me Vodaom Kolennade must sort it out witch they wont als i cant get a Invoice out of Vodacom after 8 months of trying