Talk to attorney. You may have an "implied" contract if your state honors such contracts.
Only you know the rationale for terminating escrows but if canceling escrows is such a big deal all of sudden then why pick and choose, why not just terminate them all. For those "good" customer you terminate and if they really want to continue the escrow are you going to make exceptions?
I am not a proponent of picking and choosing customers to satisfy the "needs" of the financial institution when they have decided to eliminate a service.
The opinions expressed are mine and they are not to be taken as legal advice.