You can receive a rejection "Service line COB "when you submit a claim to secondary insurance when the primary insurance payment details posted are not correct or incomplete.
In the screenshot here, the billed amount is $150.00 but if you combine the adjustment, insurance payment, and the patient's responsibility the amount is only $120.00.
Since the charge amount is not matching the primary insurance payment posting details of a $150 total billed amount, the claim is rejected as “SERVICE LINE COB AMOUNTS FOR EACH PAYER MUST EQUAL LINE ITEM CHARGE AMOUNT”.
To fix this denial, please refer to the original Explanation of Benefits and ensure that your billed amount, the payer's payment/adjustment amounts, and the patient responsibility amount all match and all charges were considered and processed. If not all of the charges were processed, you can reach out to the specific payer to see if the charges were processed on a different remit advice.