I experienced this a couple of times. The provider contacted his lawyer. The lawyer went to court and had the levy thrown out. The insurance company never allowed the doctor to go to the court hearing to plead his case but because the doctor never got a notice to appear, the judge found in favor of the insurance company. State Law may demand a judgement be issued before a levy can take place.
Right now, Aetna is involved with another class action suit regarding their refund demands. As stated, it may be possible the doctor doesnt owe the money. It could be a simple mistake. You may also have a state law regarding claims for refunds. For example, one state has a law that says an insurance company has 30 months to submit a claim for an alleged ovepayment but if it involves eligibility, then its 13 months. The insurance company cannot peform takebacks without written permission of the provider. This could be supeseded by a provider contract,.