Cell C - upgrades and contracts

Dear Cell C, I have now had 3 bad experiences since December, on the 18th of December I upgraded 1of my contracts, without any communication the upgrade what cancelled and a migration issued instead. This is is yet to be addressed or resolved. On the 12th of March I did an upgrade on another of my contracts and after being promised by the retentions department you could not offer me a device to that was unavailable - I call to follow up on the delivery today, and I get told - there is no stock??? Please can someone assist me who has some authority, I find this lack of service completely infuriating and I feel powerless to find help through your call center!