First Choice: Trade the Taurus in on a more reliable pistol. Taurus seems to have inconsistent quality control, so some samples of a particular gun will work perfectly, while others will never work well.
Second Choice: Send the gun to Taurus with a written statement that you will not accept the pistol until it works reliably 100% of the time. When you get it back, immediately check it for reliable function, and then send it back to Taurus again if it falters even once.
Third (and Worst) Choice: Let the salesman's armorer fix it, with the written provision that you will not accept it back unless it is made 100% reliable, and that the work is to be done at the seller's expense.