One out of three pendant lights on track system is not working despite new attempting new bulbs and new locations on the track. The system is less than one year old--any suggestions? Thank you

Unless you are willing to take the lock-up (part that attaches to the track) apart and check it yourself, your best bet is to find a lighting store to bring it in to.

I know you swaped bulbs with a good fixture first, Remove light from track and verify the 2 metal contacts from the fixture goes to the side of the track wit 2 contacts. Single contact of fixture goes to single contact on side of track. Be sure contacts are not bent.