Hospital payments

So the other day I was going over my explaination of benefits from my insurance to point out tho the kids father that a payment of $150 doesn't cover any thing really. I noticed that I was being charged $2060 for a unit of blood in which I had never seen over $700. Naturally me being hot tempered I would want to yell at those I know how to contact, but I kept my cool, because in reality those are the people taking care of my children not creating the bills. They kindly directed me to the correct people over at the blood bank; whom charge on their own and separate from the hospital.
As I explained to the lady what was going on she was in return explaining that they miss charged in the past and are making up for those uncharges. When I asked to to show me where those mistakes were made, to show me on the months they are making up for she changed her story to no those are our new charges. The lies now blew off my calm but I still keep my Greek temper under cool. I started to laugh and flat out said "WOW you are guys are really ripping me off! If you are charging over $2,000 for a unit of blood and my kids need mulitple ever month I will not be able to support any one to eat just to keep them alive" I demanded that I sit face to face with their department and go over every little detail of their charges and I requested the manager since I could hear her tone nervious.
The manager got on the phone I explained that there is no way a unit of blood costs over $2,000 and that I want to come in and go over all of the charges and that it is impossible in order to keep my children alive to be charged that much. He kept insisting that I do not go in and he will look at my account. He later called me and said that they found a error for the amount of $1,200 and they will correct it. In that time I was waiting for his call I went through the bills and noticed that wasn't the first time they made an "ERROR" and I mentioned that to him. He said he would do a history check on our account. I still plan on going to his office on our next visit to the hospital and my word of advice for those dealing with the hospital on a regular basis always go over your bills. Get familiar with the average charges don't be afraid to ask. It is so easy to over look things that are common in our lives, don't ever get comfortable with hospital bills.