Samwumed Approved Procedure codes and then refuse to process claim

Membership Number *** Practice Number *** Service date - 09/02/2022 ( A year later and we still battle with this claim ) Authorization number - ***6 Samwumed Approved codes on authorization and then want us to change our codes how can you approved codes as valid on an authorization and then want to turn around and stating that we must amend our codes the worse is they can't even then advice us to which codes do they want us to amend our claim.