How long will it take for them to return my garnished wages?

I would contact the creditor and demand a return of the money. If they refuse, you will have to reopen your bankruptcy case and start an adversary proceeding to get the money back.

You needed to demand the return of your withheld wages as soon as you filed bankruptcy. Then, if the money wasn't returned, file an action in the bankruptcy court. Now that your bankruptcy is closed. You can still demand the return of the money but you'd have to re-open your case in order to get an order.

I can't tell from the information you provided whether or not you are legally entitled to the return of this money or not. If you are entitled to the money, then contract the creditor to demand its return. If the creditor refuses, you will have to file a motion in the bankruptcy court to recover it. In most instances, the right to a refund of garnished wages taken before the bankruptcy was filed belongs to the bankruptcy trustee.