Non-authorized payment

How do I contact a US based Comcast billing department employee and not a 3rd party overseas call center worker?

Comcast double billed me; I contacted Comcast through chat and the person who I spoke to in the billing department stated that they had received authorization to reverse the charges and send me documentation for my records.

The chat was disconnected and none of the other chat CSRs I spoke to could reconnect me and on top of that, it seems that the billing department CSR lied to me because hours later nothing has been done and no one at Comcast has any record of any attempt being made to resolve the issue.