didnt receive everything included in the contract i signed up for

i recently upgraded my contract and am paying R1300 a month. i specifically chose this contract so that i could receive more minutes so that i don't have to purchase airtime. The contract came into effect on the 1st of April and i have not received my minutes. i then called the call center to log a request. my request was logged and resolved but i still did not received my minutes or any communication on why the request was closed. i had to then call the call center again and was told that my request was closed because i had used all my minutes. i explained to the agent that it was impossible for me to use 75 minutes in 4 days and then he went on to say he can see calls were made by me. i explained that yes, i had made calls using the airtime i had purchase the month before and he kept saying he can see i made calls so therefore i used the minutes. i told him even if he had to add up those minutes they would not add up to 75 minutes as most of my calls were only a few seconds long . He also kept mentioning the previous month and i had to repeatedly say that that's got nothing to do with the new contract. eventually he said he will log a request for proof that i had used all of the 75 minutes for this month. i then also asked how can they promise that this will not happen again next month for which he could not answer. i have been with Vodacom for the last 15 years and have additional contracts with them. i have never been behind with payments and have been a loyal customer. I do not plan to upgrade or take any additional products after this horrible experience as i am made to feel like a ****