That would depend what taxes were being refunded.

If the refund was of tax that was due from the trust, then the money would simply go back into the trust.  If the refund was of taxes on your individual income, then the refund is your money.

It's a fairly simple principle, really.  The refund belongs to whoever originally owed the tax.  And if it was tax on your personal income, it doesn't matter if the trust wrote the check.