Past arrearages are now due

After 8 years of court order payments, I have been putting the money into a trust fund administered by the bank with my ex-wife as the trustee. Faithfully for 8 years every month the money is deposited (I have every receipt) Now the child support agency has filed against me that I have not paid a dime.

My ex has the bank account and the courts have ruled against me. Just because the laws have changed and I am to pay a collection fund should not mean that I have to pay an additional fee just because my ex refuses to turn over the trust fund.