I understand. I don't think all is lost here.
Hopefully you have PROOF of his receipt of your digitial notice of vacating - such as his return email? His reponse, saying, OK! And, hopefully you provided him your forwarding addres - because he can't send you an itemization without it, obviously. Nor can he send you the deposit. So I presume you gave him that.
If so, while you were in breach with the roommate, that really may NOT cause an issue because that does not negate his requirement to give you your deposit back in full within 30 days if he didn't provide an itemized statement of damages. His claims for damages may be valueless to him because he failed to indicate them in writing in a timely manner. And, his failure to pay you your dep, can mean he must pay you DOUBLE in addition to losing his right to deposit.
"Within 30 days after the landlord receives this notice and the tenant moves out, the landlord must send the tenant the security deposit balance, if the amount returned is less than the full deposit, the landlord must include a written itemized statement of any deductions for damages or past due rent.
If the landlord does not return the security deposit and statement within thirty days after the tenant moves out, the tenant can sue for the return of the deposit. If the tenant has given a forwarding address in writing to the land- lord, the tenant can recover TWICE the amount the landlord should have paid, plus the tenant's attorney fees. Suits for less than $3,000 can be brought in Small Claims Courts."
Given the fact that he may have MORE to lose than you, and HE clearly violated the deposit law, while you did not clearly do so, I think he'd be an idiot to not settle this - however, idiots and abusers about, so I'd not wait and rely on that - I'd head down to the courthouse (LT) and make the move. You COULD try just sending him the law on notice and the DOUBLE value of what you have every reason to believe you will get, and how he lost his opportunity to claim damages - and he may say, OK, here is your deposit, let's call it a day. Worth a shot. And if he does it, try to get the double deposit perhaps.
Good luck! I wish you justice here.
I hope this helps clarify for you.
Because I help people like you here, for a living---this is not a hobby for me---I sincerely appreciate your abiding by the honor system with regard to Accepting answers, by Clicking your ACCEPT button now. Feel free to follow up after, if you need clarification. An ACCEPT also assures that I can assist you again. A BONUS is a wonderful way to tell the expert her time and effort are appreciated. I wish you the best in your future.