Misleading Sales and a very dissatisfied MTN Customer

I was called by sales rep on 21 Feb who introduced himself as John from MTN regarding my upgrade that is due. He informed of a contract where I get R160 airtime and this can then be used to purchase data on the MTN app as there are monthly promos. This was the selling point as lets face it who needs airtime in this day and age. on 6 March I received the R160 airtime this is when I normally would receive my previous contract promos only to discover I cannot use the airtime to purchase data. I called MTN on 6 March to cancel and they said they will escalate. I called MTN again on 12 March as I have not received feedback only to be told I need to call Rewards Co, by now I'm confused as who are they why must I call them. Well I call Rewards co who now refuses to cancel my contract as according to them it's after the 10 day cooling off period. I obviously only discovered on 6 March when I first received the R160 airtime that I am unable to use it to purchase data and therefore was unaware this product does not suit my needs.