No Service since March 2015 incorrect billing

We have had the account since July 2014, the deposit asked has been paid but every second month an additional deposit appears on our billing. the account has been suspended. We have tried to get the account amended but to no avail. The business call centre acknowledges that there is a problem but does not resolve it. how can we be billed when we haven't had any service, this is absolutely unacceptable. Shall we regard this as the state of the country or is this just an isolated incident of utter incompetency.