We have an account we have flagged because the customer wired funds to long lost cousin oversees (the UK) to get an inheritance. We informed the customer we would no longer do these wires because it is a scam.

Now they are just writing checks to the oversees account.

Anything else we can do? We can't really stop them from writing checks.

Close the account and be done with it.

Yep

It's not credible. Most long lost relatives die in Asia.

You don't mention the customer's age. If he or she is elderly, then consider your responsibilities under state law as well as your duty to file a SAR.

Other than that, I agree with the decision to terminate a relationship when a customer simply will not listen to reason...