Upgrade

I have been trying to do an upgrade for my line and have been struggling due to stock limitations,I eventually went to iStore and found a deal I’m interested in (iPhone 13 Pro 128 on 230 flexi for R839) when trying to sign up there’s a whole lot happening that became issues whoch I never had with Vodacom, e.g upgrade fee amd also paying for the 2 remaining months on my contact….is there a difference when upgrading directly with Vodacom and doing it via the iStore?? Secondly if I upgrade via Vodacom directly,would I still be able to trade in my iPhoneX towards my contract?? May I kindly have one of your sales consultants contact me please…I would like to put this upgrade to bed and do it already