Replacement tracks for interior closet door

We just purchased an apartment with an interior closet which has 3 mirrored glass sliding glass doors. The doors do not slide and we want to replace the upper and lower tracks. The door opening is approximately 7 -8 feet and there are tracks on the top and bottom which appear to be worn. Each door is approximately 3 feet wide. Can you identify the tracks from the photos attached and do you sell replacement tracks? If yes, what do we need to order and how much are they. Thank you