Discovery Health Poor claim Handling process

Always poor handling of emergency claims. My child got injured and needed to go to ER for wound treating and stitching. Claim has been rejected with one of the same stupid reason, when I ask for clarification I get the same stupid reason that the invoice must be sent with correct ICD-10 codes, but on the invoice i can see ICD-10 codes and when i search them online i can see the codes correspond with the procedures performed. I have asked discovery to explain which codes they want and why they say the ones on invoice are incorrect... if you say something is incorrect then you must know the right ones so explain, make sense.

How will I request hospital to update invoice if I don't understand the concern raised Discovery?