Phoning for payment when you already paid. Keeps on charging

People do not know their own departments that they work in. When coming to pay your account, you do so but still get phone calls throughout the month saying that you need to pay. Each time they phone you have to pay for it even though I already payed for that month. It's just a way for them to make more money and the people in the account department are so useless that they can't even help to stop the phone calls. As in the building trade I spend thousands a month and hate having to go to them. So over priced but unfortunately sometimes they are the only ones to have what is needed.