Charged more than Quoted Monthly Contract Fee on Invoice

Vodacom Mondo Rewards made a direct marketing offer to me on the 24th of March 2019. The offer was 10 GB per month on promotion for R149 per month. I have taken out a Vodacom Mondo Rewards contract before, 5GB per month for 24 months in 2018 with no issues so I agreed to the offer. According to Vodacom social media Facebook team and Vodacom Mondo Rewards, the quotation stated R149.01 per month. Vodacom charged me a pro-rata fee on the 28th March of R28.84 which was expected and fine. But then they sent me an April invoice of R162.00, with no added pro-rata or any other fee but the contract fee. They are telling me that they are charging me less than R149 monthly but this is clearly not the case according to the invoice total. There is a consumer protection act in place that differs with their opinion. Suppliers are not permitted to mislead consumers in respect of pricing, the nature, properties, advantages or uses of goods or services advertised, if such goods or services are not actually available for purchase or procurement in accordance with these standards. I have been misled because I've been invoiced more than what I was quoted for the service contract.