Billing dispute

Hi,

I am a Cox customer for last 9 years - in my recent statement, I was charged an equipment adjustment fee of $57. When I called in, I was told that this is something about a cable box which I still have. I had called multiple times to communicate that I do not have any cable box with me. Last time, I was on call with customer service and then they transferred to loyalty and finance group and they talked to me for last several minutes and the line got disconnected. No call back and no resolution - this happened on 5/24 at 7:45 PM ET. I would really appreciate a response - thank you