Vodacom committing *****!

I am not impressed with Vodacom AT ALL. I am due for an upgrade for my contract which is for my tablet. I was informed in a store a few days back I can only upgrade in Oct this year. I also checked my app and it reflected the same. Today when obtaining my new tablet, I was informed I cannot upgrade. Apparently all of a sudden my 24 month contract I signed for is actually 36 months???? The consultant assisting me (who is doing her best to assist and get to the bottom of it) contacted the help line to find out why it would allow my upgrade. The system said it is due this month. Long story short...I went on my way and she called me back to say app my contract is 36 months and I am due in Dec. I went with all my original paperwork which reflects 24 months, but in the description it says 36 months. I was billed the contract amount in my first month and I am still being billed the same. My invoice reflects a 24 month contract. Now, if it has "changed to 36 months" then why would I still be paying the amount which is for a 24 month contract? This is *****!!! After going back to the store, all of a sudden after speaking with the help centre, the system now says I am due for an upgrade Jan 2020. How can it change, this is also *****! I have all my statements and invoice reflecting 24 month contract payments, I even located the brochure in Jan 2014 which shows the special I took...R199 for 2gig Samsung Tab E. I want this resolved asap. The consultant helping me is being incredibly helpful and she will try get this sorted. I hope between my complaining and her trying to help me, this gets sorted out asap!!!!!! Otherwise I will take it much further as I feel this is complete *****!!!