Bottom wheel slider part# 4350145
Thanks for writing in! The roller in your photo appears to be the 23-098 Mirror Door Roller. To confirm that this is the correct replacement, carefully look over the dimensions below and compare them.
I'll need to see the a photo of the top guide to identify the correct replacement.
You'll need to examine both the bottom roller and the top guide for any damage to determine which of these pieces of hardware need to be replaced. I'm sorry to say I would not be able to confirm the issue from the description above or the photo you've provided.
To obtain a replacement for the sliding closet door, you'll need to reach out to the manufacturer (if you know who they are and they are still in business) or a local closet retailer. Unfortunately, we do not manufacture parts or make doors of any kind.