2.2 gearbox

just before christmas my gearbox went in my zafira b (2 years old) it would not stay in 3th gear it was still under warranty so the dealer ship put a new 1 in they say they dont know what happened it and they had to send it to vauxhall it was the 6 speed box they also had to replce a control box that works the door locks to open/lock when you press the sensor on the door handle and also when you push the start/stop botton on the dash
anyone else ever had these problems

zafira