Ford Focus automatic shift issues

I have been dealing with automatic shift issues on my 2012 Ford Focus for more than a year. The car has gone back to the dealer more than five times to investigate grinding noises in the gearbox. I have had a situation where I have lost drive in traffic and have had to stop and re-start the car. The transmission has been removed and the clutches replaced. It has also had five “re-learns”. For a new car this is totally unacceptable. I have also logged my concerns with Ford, but they always refer me back to the dealer. Whilst I love the car, I firmly believe that a new gearbox will solve the problem. Where should I go from here?