Becareful for hidden fees after canceling your contracts!!

I paid up and canceled my contract at the end of February. I was given a settlement quotation of the outstanding balance (or what I thought was the outstanding balance) which I settled thinking that the contract is paid up and canceled. Though out my interaction with every consultant that I spoke to I confirmed if the settlement amount was the only amount that I had to pay, which I was assured that it was.

To my surprise I received a statement today with an outstanding amount for March. I contacted customer care to confirm why there was an outstanding amount if I "settled" the account. The two consultants in customer care and collections were very helpful and understanding and tried to explain as best as they could, but what I don't understand is why provide settlement quotations to clients if there is going to be additional accounts after you cancel it? Why not be open and honest with your clients and explain the possibility of future accounts. I am now in arrears with an account that I was under the impression was canceled and closed.