Summons without notice

I sign a contract with Vodacom then I decided to cancel it I went to galleria mall they gave number to call but they continue to take the money from my account I call again they said to me I was suppose to call again I asked them how much I owe they said 500 and something then I paid it in April On the Friday I received summons for 445.07 I was so agry why they didn’t tell me about this money before I call them Saturday they said is a balance of subscription they are having my email they suppose to send this owing in time not come as summons I’m so disappointed I will never go for Vodacom