Citibank Credit Card Complaint

Citibank Credit card department,

Transaction issue California

I received and activated Citi Costco Visa card. It was supposed to replace - - card. My - card stopped working and Citi Visa although activated successfully - is being declined by all merchants. All calls to Citi result in the message : " We experience a large volume of calls. Call us back some other time ''. I tried calling and emailing Citi for last 24 hours to no avail. I am traveling today and unable to pay for food, transportation, lodging or basic necessities as I traveled with only - and Citi cards.