Store refuses cancellation of contract within 5days

I went to Vodacom century city to take out a contract. I was looking for the iphone 15pro and the store did not have in stock so the agent said they only have the normal iphone 15 at the moment i was okay let me take it. Ever since i took out the contract on the 21 October 2023 i was not happy with the phone. I was not in capetown and returned today the 26 October 2023 i went to the store to cancel the contract after contacting Vodacom numerous times where the cancellation department told me i should take the phone back with the box the store is the only place who can cancel the contract as i have 7days of purchase to cancel the contract . I arrived at the store where the manager Morne refused to cancel the contract as he said i signed a legal document for 36months so i cant cancel it . I only have the phone for 5days now very disappointed and the store refuses to cancel the contract and refuses to give documentation stating i am not allowed to cancel the contract