Tracks and light fixtures have to match. Yours are Hampton Bay but it's likely the style has been discontinued.

These pendant fixtures could be used as replacements.

https://www.homedepot.com/p/Hampton-Bay-Mya-1-Light-Satin-Nickel-Track-Pendant-PN-1MYA-TRK/203718054

I have 2 over-counter pendants on a H track system. One of the pendants no longer lights. We've traced the problem to the H track system itself. The contacts don't always reliably touch the "live" inside portion of the track. What a pain it's been. I like the lights themselves but not the track system.

Dear Beverly, I did see that option at Home Depot but was not in love with them and was hoping to find an alternative. Thank you though for searching for an option for me, I appreciate it big time. I found a couple on amazon but it's from a company that has absolutely no reviews so I was bit nervous to buy from them. I'm just so surprised how difficult it is to find flexible pendants that can already plug into my pre-existing track!!

Since you have not discovered the problem is the track, why not purchase a new fixture as these look very old, or at least consider a company that makes and sells good track lights. Consider Juno or Halo.

I would just change out the track there are very nice ones and now of course LEDs .HD is not where you go to find good lighting.