Contract mixup

<p>Good day</p> <p> </p> <p>I received a call to upgrade my current contract of 2GB top-up (R109 per month), with an addition of a tablet it was supposed to be R139 per month, to my shock i reveived the invoice for this month and it says i owe R 12 626, i contacted your helpline and they couldnt help me and said i had to wait 7-14 days while they still investigated. during the waiting period, my account will be debited for that riduclous amount.</p> <p> </p> <p>My profile says my plan is 24month contract which is untrue becasue i made it very clear that i was on a 24month top-up contract. why was my plan changed?? , without my knowledge??</p> <p> </p> <p>Please assist as soon as possible, I have been a loyal vodacom customer since 2002. </p>