When IRS makes the direct deposit into the account specified by the taxpayer, then they have fulfilled their legal obligations. If you are able to get the check refused by the banker of the UGMA/UTMA account and returned to IRS, then it will be back in their hands to take the next step.
You should be able to speak to the administrators of the UGMA/UTMA account at the bank and explain what happened. They should be able to see that it matches your story and discuss any options you may have.
