Complaint Phone Calls to Citibank Customer Service

I am the POA and Trustee for my Aunt, Maxine V Williams, whom is 101 years old.  Maxine lived with me in Kingman AZ, which is a minimum of two hours from a Citibank Branch.  Maxine passed on November 11, 2016, and I was unable to resolve an issue with through Citibank customer service over a three month period beginning in September, before her death to prevent her account from being over drawn.