JPMorgan Chase & Co. Credit Card Complaint

JPMorgan Chase & Co. Credit card department,

Billing disputes New York

I am trying to contact my bank regarding a dispute. I am calling the number on the correspondence I received in the mail from the bank. When I call, I get prompted to leave a voicemail for the Merchant Disputes - department, but the voicemail system then plays a message that says the mailbox is full. This has happened several times over multiple months. I called the customer service number for my bank and got a transfer to the disputes department ( onshore ), and told them that I was trying to reach the agent working my dispute offshore. I gave them the same information from a letter I received, dated -/-/-, and they were also unable to get through. The number is -.