Did you try bringing in your divorce order to the bank and asking that they file it in their head office to remove you from the mortgage?
Legally, you are not responsible for the mortgage on the date that the court order was granted....so the banks will recognize it when you take the order in. The bank should take a copy and make the necessary changes. I'm hoping your court order states that you bought him out...
A similar incident happened to me but it wasn't the mortgage...and I took the full court order in and got the banks to change things.