We are having zero luck contacting the originator to try to resolve the $2,800.00 transaction.
reach out to your local NACHA regional association, or NACHA directly, and ask them to help you file a NACHA Rules Violation, that will get both the ODFI and Originator's attention, and get you a response. The ODFI/originator is responsible for providing proof of authorization within 10-days of your request, so if they are not doing such they are in direct violation of the rules. use them to your advantage. the ODFI may agree to a late return and charge back to the originator, I have seen this more than once.