Hiring the wrong tax representative.

One of my clients hired a tax representative to help them with a sales tax audit. The audit resulted in a sizable tax debt. and penalties were assessed. The tax representative protested the audit and filed a request for an appeal. Of course the representative billed the taxpayer for services. When the taxpayer did not pay on time the representative withdrew the appeal leaving the taxpayer with all of the tax debt. Do you feel the representative should have withdrawn the appeal? Do you feel this was unethical.