Citibank Credit Card Complaint

Citibank Credit card department,

Customer service / Customer relations Pennsylvania

Hello, I have called Citibank for a total of three times with an unresolved issue. My account has been locked. When I called Citibank, they requested a phone verification in order to verify my identity. I provided the home number of my father, an authorized user, which they called and provided a reference number. When I called back with the reference number, the bank further refused to verify my identity and asked for a fax of my ID as well as social security card. I am currently living and working abroad and unable to as well as uncomfortable with faxing sensitive information to the bank which I can verify over the phone.