Misleading information

I am very confused with DH’s reason code and descriptions. A recently claim was not fully paid and the reason stated “You do not have to pay this amount”. For any normal person this means “you dont need to pay anything”. But then I was contacted by the doctor to settle the difference. I called DH and was advised that I am liable for the difference. Why the hell do you say on the statement “You do not have to pay this amount” if I cleary HAVE to pay it??? This is quite misleading and even the agent could not tell me why this reason was on my statement.