Legal Question in Business Law in Illinois

Since your husband did the work, he should get paid. You don't say what the emails contain, though. Does the DJ company acknowledge in the emails that your husband did the work? If not, do you have any proof that your husband did the work or what the terms of payment were?

In the emails, does the DJ company raise any reasons for not paying your husband?

Unless there are important facts that are missing, and assuming your husband has some proof that he did the gig, your husband should be able to be paid.

He could file a small claims case against the company. He has to decide whether pursuing this in court, with the time it takes to write up the complaint, the cost of the filing fees and then the time required to show up in court is worth it.