Trouble during payment process: Mortgage

U.S. Bank applied or increased default interest on my mortgage account due to alleged back taxes and/or payment issues, but I have not been provided clear written notice, an itemized explanation, or online account access to verify the charges. Instead of receiving a clear written explanation, I received a voicemail. I do not have online access to review statements, notices, payment history, escrow/tax activity, or the calculation of default interest. I am requesting that U.S. Bank provide a written explanation of the default-rate provision being relied on, the date default interest began, the default interest rate being applied, the tax/escrow basis for the charges, all notices allegedly sent, a complete transaction history, and a current itemized reinstatement/payoff breakdown. I am also requesting that U.S. Bank explain why I do not have online access and provide a reliable method for receiving statements, notices, payment history, and account records going forward.