Telkom sold me a contract under false pretences

On 14th March I went to Eastgate to get a cellphone contract. I already have a handset and wanted a sim only contract. The sales clerk advised me on the smart plan 100 contact,whereby I would receive 100 minutes and 1 gig data p/mth for 24 months at R99 p/mth. This was the 2nd time I heard about this contract. The same information was given to myself at the Lakeside Mall 3 weeks before,however they had no nano sim cards in stock for 3 weeks. I therefore decided to go Eastgate. After the sim card was activated,I used 89mb of data when I received a sms from Telkom stating that I ran out of data. This seemed all wrong,even if I did only get pro-rata surely it should have been +/- 500mb. I called the helpline and a call centre agent by the name of Brice agreed that something was wrong. On the 24th I received a call from Telkom and the call centre lady said that due to the contract being a sim only contract,I will not receive 1 gig data. I spoke to the manager,who said I was welcome to cancel the contract. This was not what I was sold and what I agreed to. I have 2 voice recordings of Telkom staff explaining the smart plan 100 sim only contract and all of them has a 1 gig data included.