It's shocking to me how many people will outsource their sales tax reporting to a vendor and never speak with the actual person who will be doing the work. Yet every day companies entrust millions of dollars in tax reporting to someone they've never even talk with over the phone. To be fair, they've talked with someone at the company, and they've likely checked references, but they've never actually talked with the person that's directly responsible for the work.
There's often a veil of secrecy around the person doing the work. Companies hear that the "process" is more important, and the group is led or managed by sales tax experts. That's fine and good until you learn your day-to-day contact has never seen a sales tax return, has never worked in a tax department, and may not even have an accounting background.
What invariably happens is that your day-to-day contact is gone in three months. They’ve moved on to a new company or they were dismissed. Or maybe you had a great resource that has now been promoted. Whatever the reason for the change, your cost and risk increase. You have to re-invest time in training the new person and bringing them up to speed on your business. Any unique processes that were implemented for you are likely to go out the door with the resource as well.
Turnover and the resulting issues are a direct result of the way most outsourcing firms deliver their service. It's all about setting up a factory, running you through their factory in a way that removes flexibility all in an effort to drive down the cost per-transaction. This flawed approach actually yields more cost and risk as noted above.
In the future, demand to speak with THE person that will be your main point of contact. Treat this like an interview. Ask for their resume and interview them as if you were hiring them as an employee. After all, they really do work for you.