Complaint

I took out a month to month rain contract sometimes last year, and was told by the agent then that I will pay and then get the service, so no payment no service, on the 1st of march i did not have enough money in my account for the R265 premium and I assumed then that there will be no service, and samething on the 1st of April no payment, however to my surprise I am told by Rain that I owe them R530 for 2 months of which I did not use their service since their sim card was blocked/suspended or stopped Im not sure but it stopped working around the 2nd or 3rd of march of which I understood because I did not pay What I dont understand now is how do I owe them when they told me initially that i pay upfront and then get the service and I have not used their service since the beginning of March, they are now telling me I am being billed for the service I have used already of which its not what I was told in the beginning of this contract, I am very dissapointed in them,I now want this cancelled and that balance owing reversed as this is not what they told me in the beginning, the agent I spoke to just now put the phone down on me,yet Im the one who called using my own airtime to try and resolve this