Fitted new ballast to nearside front headlight, now working but drivers side headlight that was ok now isnt working, any ideas

Hey everyone

My nearside headlight on Bongo isn’t working. Just fitted new ballast and still not working. Anyone got any bright ideas on fixing it pls MOT due next week.. 🥴

Hi

Got a 2001 Mazda Bongo. Nearside headlamp u/s. Just got replacement ballast from china. Has anyone got any tips in fitting it. Cant seem to get bulb holder out! TIA