Hoping you guys can help me out- no luck with Customer Service.

I am helping my grandfather add his UPS account # from a 3PL into his Amazon Seller Central account and we keep running into the same issue. Customer service has been no help because I do not have direct access to the seller account.

When adding the UPS invoice information, it returns an error that tells us to contact customer service. We have tried everything for the invoice info, even trying a different invoice and still running into problems. Tried case sensitive, leading zeros, and trailing spaces and still getting input error.

“Sorry something went wrong; Please double check your input and contact Amazon if the problem persists.”

Anyone been through this and know what we could try?

TIA