You are saying that you were never notified in 2 years that you were behind in child support payments? Not by the court, not by the mother? I find that hard to believe
And why was his employer sending in the child support payments instead of your boyfriend? And your boyfriend never enquired about if in fact he was, never asked to see a child support payment receipt? All child support payments have receipts attached to them, as proof of payment. You boyfriend never asked to see one, never went to the court house to check on it? He never asked to see a canceled check made out to the court house friend of the court, or the mother?
The friend of the court would be all over him (not his employer) wanting to know where the child support payment is, trust me that office would not take 2 years to contact him
Pretty irresponsible I would say of him, trusting an employer to make the child support payments for your boyfriend. Sounds like he is telling you a story because now he is in trouble.
If the payments were going directly to the mother, you are screwed as there is no proof of anything
If in fact what you say is true (again, hard to believe), he will probably owe the money.