Blue Cross Blue Shield (OK) Customer Service Issues

I had an issue with an LPC not aware of a client having BCBS and Sooner Care, needing the EOB for OHCA. When billing BCBS claims, I was requested to provide W-9, Provider Notification Form, NPI, address, and phone number multiple times since August. Despite sending the information with claims four times and ensuring our agency's details are updated in Availity, I keep receiving letters asking for the same details and to resubmit claims. I attempted to contact BCBS without success, only reaching an automated line. I seek a contact number to a department where I can speak with a person to resolve this issue and understand why the requested information isn't being processed correctly for claim approval. Thank you, Chris R.