Wrong information, no liability, faulty equipment

I went to Vodacom shop in Three Rivers to upgrade my contract for my company Farmari Boerdery. the assistant then informed me that if there is any faulty products that I bought during my upgrade, Vodacom will exchange it immediately. I bought the Samsung S6 handset, from the start the handset did not last a day before it must be charged again, even at night if we charge it 100% the next morning the phone will be at 80%, all the apps off and the phone was not used until the next morning. I phoned the shop at Vereeniging, and was informed that if I bring back the handset, it must be send away for 7 days and after that Vodacom will then decide if they will exchange the phone, that means that I will be without a handset for 7 days on a brand new contract. I then informed them that i want to cancel the contract, and was informed that I will pay penalties to cancel the contract, even thou it been less than a week. This is my second run inn with Vodacom, it feels that our money is good enough but we do not have any control over the service that we pay for.