In this internet day and age - you should expect to get access directly to your customer service representative via email. And you should expect a reply on the status of your case within 48 hours. Need to talk about the deeper issues related to your tax problem? You should also be able to call your representative and have their direct line.
What does NOT work in the realm of customer service? Hiring someone and the person who did the "upfront" analysis of your case and who received your payment- no longer having accountability to you and your case. That is an unsustainable model and a model which sunk many of the Tax Resolution Companies you'll find on this list.