Unhappy with vodacom service

i am an unhappy vodacom client, i have a cellphone contract with this company which was due to expire in January 2018. I visited vodashop in Thohoyandou to cancel the contract and was shocked to learn that ive upgraded the contract in November. i told them that i did not and they informed me that they will investigate the matter. i have called numerous times and i am not getting any assistance. They asked for my id copy and 3 sample signatures and an affidavit, which i gave them, but todate i am still waiting. Since then nobody at vodacom has repondonded.All i want is to cancel the contract and not upgrade, i am frustrated. i dont have time to be running after a service provider.