AmeriGas Propane

I am not sure where to go to for some help on investigating a company that I feel may have some interesting and criminal billing techniques. I am filling a compliant with the Iowa Attorney General because what they are doing is a crime.
The name of the company is Amerigas from Davenport. The person that my husband talks to when he calls in is Tabitha. She processes the order and completes the billing. My husband found it interesting that she did not even have to look up our account or the date to see what kind of error could have been made, she simply replied "Oh, everybody was billed incorrectly that day and we just haven't gotten around to sending out a new bill." He did not even give a date for the delivery or the date on our bill.
The last three times we have had errors in our billing and each time it has increased in cost to us. The company does correct the error when we call them on it and they use the same statement every time. "Oh, everybody was billed incorrectly that day and we just haven't gotten around to sending out a new bill." Or "I was going to call but I just didn't get around to it." We were even charged for the twenty gallons that we still had in our tank. They said they delievered 250 gallons but that is all that we had after they delivered our gas.
We have resolved the over charge issue but we are unsure how to recover the cost of the 20 gallons that we already had in the tank. We are extremely concerned that this same technique is being used on other consumers, and the elderly and less capable consumers may not be able to help themselves and would be stuck paying an inflated bill.
The last time we ordered gas we waited for over a week to get the delivery. I know that propane is in short supply for the farmers so I attributed the wait and cost to this shortage. Usually, when we call and order gas they will quote us a price per gallon. The usual billing errors are the price per gallon increases when we get our bill. We call them and tell them our quoted price and they send a new hand written installment payment contract. This time when my husband called they did not quote a price, nor did they include a cost per gallon on the delivery ticket. We generally make our payments in four installments. When we received the bill we were shocked that the propane could possibly be over a dollar per gallon higher than usual. We received the bill on the 1st of December, my husband decided to do some checking on what propane was going for per gallon with other suppliers-- they were more than $ .80 to a $1.00 per gallon cheaper. When he called the company they replied with their above statement and said they would send out a new contract. This will be about $200 cheaper than the first bill.
Here is our concern, we have our tank from this company and are required to buy our gas from them, we are in the process of looking for a tank to purchase so we can shop for our gas- we are concerned about the elderly or less capable customer who would not question their bill and just pay the bill even if they could not afford it. I know that my mother-in-law would pay the bill and not question it even if it emptied her checking account.
I think since this has happened to us on three occasions and this last time to the tune of $200 someone needs to look into their billing practices and save someone who cannot protect themselves. In addition to the overcharging my husband told me that they charged us for 250 gallons but we had 20 gallons in the tank when they filled up and now there is only 250 gallons after the fill. There is no way they could have delivered the 250 gallons that they are charging us for.
I do find it kind of suspect that they could have made the kind of error on our bill that they did if they did not intend to bill us what our installment contract states. The bill was hand written, not computer generated, and would have required someone to figure out the total and to decide what each of the four payments should be. Someone please stop this company from ripping us off!

The company in question:
Amerigas
7221 Gaines Street Court
Davenport, IA 52806
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