Having also been there, this was not my experience. The IRS sent me a bill for $1500 claiming I had taken an early deduction from my IRA. I had, but it was only to correct a mistake I made right before of contributing too much for a given year. I filed paperwork with my brokerage at the time to reflect this, but apparently the IRS didn't get that.

I replied to the bill with the relevant paperwork and a 1 page letter explaining what happened, and the IRS agreed I did not actually owe them anything. No lawyer required.