Vehicle loan or lease — U.S. BANCORP (PA)

Billing problem. I received a used boat loan for {$110000.00} from US Bank, account number XXXX. I pay twice per month and the loan has provisions that it can be paid off early. My calculations show that I owe {$1000.00} less than what US Bank shows. I have called US Bank on several occasions to get an amortization breakdown, and they refuse to give me anything in writing. One representative even said that they will not give this in writing, and another representative said they will only give it within the first six months of the loan. I have called three times, and all three representatives say they would send, and I have received nothing. There is an issue here, and no one will give me the calculations.