changing of accounts and withholding information

we paid less than we should have for our contract this month by mistake we wanted to know how mush we must pay today to rectify our mistake and to change our payment method. they advised that our account was not in arrears and that our method was already changed. when I ask when they said they do not know.<br> <br> we phoned the second time only to find out that they send our account to legal because we were in arrears for 3 moths. they gave me a number for their legal department that do not word.<br> <br> we phoned a 3rd time to get the correct number they told us we are not handed over and that we must pay an arrears of x amount again after we requested a settlement amount in October of all outstanding arrears which they gave and we paid.<br> <br> we are now trying to get the full amount to pay again with no luck and they do not want to help with the cancelation department number.<br> <br> where can we report them to.