Upgrade gone sore!!

I have a 20 gb data plan contract with vodacom since 2017, after a smooth sailing 2 years it, was due for upgrade in feb/march 2019. However I didn’t make any changes to my contract, i stuck to the same 20 gb data plan, this tomorrow around the monthly installment was a bit less because of a promo Vodacom was running at the time of the upgrade, i was told my monthly payment would be R260. But not once since this upgrade have i paid that specific amount, the trouble started in April when I received a statement for an amount of R1180, Vodacom then confirmed it was incorrect billing on their side and the statement was corrected, yet they still tried to debit my account twice for that amount even though i paid the “correct” amount in store, May month i get a statement of R406 including a unpaid fee of R100 because vodacom couldn’t get the R1180 which they incorrectly billed me for. A few days ago i get my June statement which is now R556 or something to that effect, including insurance which I never had on my accounts for 2019 as I cancelled it last year and i NEVER REQUESTED for it during this time, there is also a charge of R256 which the call centre says is for a game I purchased on 26 April, but funny enough my statement for May which I received on 10 May 2019 does not have a charge for this supposed game I purchased, it’s only brought to light in June, don’t Vodacom debit you for your previous months transactions? Why is this supposed purchase coming on my statement almost 2 months later?? I would like to know if it is a norm for Vodacom to be in breach of legally signed contracts? I signed for a 20gb data plan for R260 but I have never paid that specific amount? Is it too much to ask for someone at Vodacom to do there jobs properly? I did not ask for insurance on my contract and I certainly did not purchase any games.. i want Vodacom to supply me with proof, that i made that purchase for that game, I refuse to pay for a service/game i NEVER app**** for and I’m completely disgusted that after 2 years of having this contract this is the level of service I’m receiving from vodacom.. I have never missed a payment on my contract, i never had any reason to ever contact vodacom for any reason and vodacom never had any reason to call me regarding payments or anything on my account. But after this upgrade, all hell has broken loose, and to top it off, in April i had to pay unpaid fees to my bank too for the R1180 debit order that vodacom took twice, causing my account to be overdrawn and also in turn affected my home loan application that i was busy with at my bank.. i work hard to maintain a good credit record as well as have my bank account in good standing but then vodacom messes it all up, and even ghoul I requested a letter of explanation from the call center, to hand into my bank, i am yet to receive it.. All I want is for Vodacom to sort out this account and charge me the correct amount according to my signed contract, without me having to phone your call center every month and spend a good 30-45 minutes of my work time on the phone.