Mondo sold me a contract under false intentions

In May 2015 a sales rep from Mondo phoned me on my Vodacom cell phone and said they can see that I use my data bundle of 500meg on my smart L package quite quickly. Therefore they advised me to purchase another 2 gig p/m at a lower rate. Since I do have to buy extra data each month, the deal sounded attractive and I agreed. Two months down the line I realised that I am still running out of data regardless, and the monthly fee they quoted is being debited from my Vodacom account. <br> After enquiring Vodacom informed me that they have sold me an ADDITIONAL contract with another cellphone number, hence the mobile wifi ****le they gave me in 'addition' to the deal. I did NOT want an additional contract but I only agreed to the extra 2 gig on my existing account. <br> I want this deal to be rectified according to the way it was presented to me over the phone, alternatively it should be cancelled. My ref number at Mondo is \747". In the 5 months since signing up for the bundle I have not used a single meg "