Name change for child

Nebraska-I have a question. My ex-husband adopted my son. At that time, we changed his first name to his middle name. Now we are having problems with insurance, papers, school, etc. I contacted a lawyer to ask about name change and was quoted $400.00. Can't I do this myself? When I asked about paperwork at the courthouse, I was told I have to have a lawyer. Is this true? Thank you in advance.

Different courts require different things.

$400 does not sound like an unreasonable amount. It's quite low if you ask me.

I am having a problem understanding. IS his name legally changed? AND what is the problem that these company are giving you?