Why am I paying $200 to get access to "tax experts" when they mess up our return?

This year my wife and I paid $200 for the expert review given we were submitting travel expenses for the first time.  I had two separate tax experts review; the first walked me through the process, then I had a second review again just to make sure everything was done correctly.  Both said they were.  I then get a letter from the CRA in October stating the travel expenses were incorrect and I owed the CRA $660.  This is frankly egregious.  Either TurboTax fixes this situation or we will not be using them ever again.