Unable to add payment method on my client's AdWords account. Error: OR-IEH-01
I've been unable to add a payment method for one of my client's AdWords accounts for nearly 7 days now. I keep getting an error message that says "An unexpected error has occurred. Please try again later. [OR-IEH-01]" (see screenshot below). I have attempted to call AdWords support 3 times and each time the issue gets "elevated" but each time I get a call back I get a different answer ranging from, "use another browser or incognito mode", "there must be a problem with our billing system", and "please try again tomorrow". Obviously none of these solutions works and there doesn't seem to be a way to reach out to the billing/payments department directly for assistance.
The funny thing is I can update payment methods on my other client accounts but not this one.
If anyone at the Google payments department can please reach out to me it would be most appreciated. This problem is going to cost both Google and I this client if they cancel their service.