Vodacom V-UP - Possible ****

I’ve been contacted in a very suspicious way regarding Vodacom’s V-UP competition. I’m being asked to purchase OTTRewards and the contacts as well as the account name are not consistent with what’s been registered with Vodacom. Their sms is also not very well written. Can someone please confirm if this is legit or is it a ****? I’m being asked to provide the reward numbers over the phone - this does not seem right.