Still not getting my itemised bill

I have not been receiving my itemised bill for the past 3 months. I am paying for the service yet I have to waste my time and money phoning the call centre and waiting an eternity for service. Once I get through the bill gets sent manually and I get told a log is made with IT and then when I call back the next day I'm told the issue is resolved.. only to go through the same process again the next month. Nobody seems willing or able to help me fix this for good. Its not a problem with my details as my invoice gets through when its time to pay the bill! It is not a free service, I am paying for this service and expect to get what I'm being charged for. I can never get to escalate to a manger as one is never available and I'm now at the end of what I am prepared to tolerate. Plus the fact nobody ever calls me back is completely unacceptable.