Cell c billing me for an already canceled contract. With ref and everything

So on the 25/4/2019 I phoned into cell c to find out about my contract. I held on for more than a hour and finally came through to Akshef( not sure if thats the qay you spell it). Upon speaking to him he informed me that my contract had been canceled according to me was the correct time as it was a 2 year contract. So yesterday being the 6/5/2019 I received an invoice for exactly the same contract of which I havent even been using the data. I unplugged the modem aswell because he said that it showed that it was pay as you go and we weren't using the modem anymre. Mind you we were given a reference number also being - ********** ********** 61. Which to me was a canceled contract. ( of which we were so happy that was ending because ever since we had the thing we weren't able to fully use it n cell c rep**** with the response " oh well you should still pay ") so we did that for the past 2 years just waiting for this contract to end. So imagine my excitement wen I was told that my contract was canceled. Was the best day of my life. Today being the 7th May I wrote a review agen yesterday n was told it ends in june. So ***??? This is day light *******. You guys ****** me for the past 2 years and now you want to rob me a further 2 months. When is this going to stop???? Anyone thinking of gettin a data plan plz don't go to cell c. They ******* and if you have a problem they dont do anything to help. Its all about payments and no client satisfaction. Rather go to telkom. Their data is cheaper. N connecting to internet has never been easier.