Husbands Employer Attempting To Withhold Final Paycheck As Previously Uncollected Escrow?

Location: Chicago

Sorry if this is long but looking for some advice on whether we need to hire a lawyer or just submit a complaint to the state.

My husband started working for a flatbed trucking company in Chicago on 3/31. When he was hired the owner told him they would start collecting a $2,500 escrow ($250 a week for 10 weeks) after his first 3 months to give him time to get settled. He was working as a 1099 company driver which as far as we know is illegal so they shouldn't have been collecting an escrow anyway but it was a quick hire and he needed to work.

The contract he signed says that all employees must give 2 week notice before resignation and failure to do so may result in loss of compliance bonuses and/or escrow funds.

On 06/15, he tried to quit midday. We recorded the phone call with his boss saying that he had to give a 2 week notice if he wanted to get his money. So my husband gave a written 2 week notice that day (06/15). A few days later, his boss told him he could be relieved on 06/22 instead because they found another driver so 06/22 was his last day. He even ran into his boss at the parking yard on his last day and they had a friendly conversation.

He was supposed to get paid 06/26 but we've figured out that the guy has blocked his number and is withholding his final check which is coincidentally around $2,500. Maybe he's gonna pay him a few days late sure but now we have no way to confirm this since he's blocked.

How can this guy be collecting escrow after my husband gave notice and the truck was returned in the same condition?

My husband has a ton of other things to hold against them like forced log book violations, faked inspections, racism, hiring foreign dispatchers under fake ssns, tax evasion etc but he seemingly doesn't care. He doesn't even really want to get him into all this trouble but just wants his $2500.

Where should we go from here? Do we need an employment attorney or should we just file a claim with the Illinois Department of Labor?