You'd of been better checking it was the bulb before buying one. IMO, if its just stopped working it wont be the bulb, they go pink before they die.
Either your ballast has died (which is common) or the igniter has become disconnected or even broke (which is uncommon).
Best way to test would have been to take the bumper off and swap the ballasts over and see if the issue still occurs. Repeat for the igniter/bulb.
I have exactly the same problem , i repalced the bulb and the ballest (if thats the black box that clicks onto the bulb) and it worked for a few days and its gone again now.
Anyone have any idea what else i could try?