Drivers side window part question

2004 with electric windows.
Lowered my window yesterday and it never came back up. Took the door panel off and found the regulator arm had come out of the channel(mounted to the bottom of the window). Looks like a small plastic piece, that holds the regulator in the channel, had slit in two.
Does anyone know wether this piece can be found on its own, or is it part of the regulator assembly? I couldn't find a separate part # for it in the parts manual.

for any help

Many people have had this problem.Mercedes would like to sell you a $250 unit replacement. I used a 5/8 inch shower door roller.If you search you can find several threads with photos on how to do it

try this

https://www.youtube.com/watch?v=hWqjtAYFMTw

Sounds like yet another application for a 3D printer...
(but a Home Depot shower door roller is a good substitute)
Sikwan's "how to do it" thread
...followed by his updates after one of the replacement rollers disintegrated:
https://sprinter-source.com/forums/showpost.php?p=301376&postcount=39
and
https://sprinter-source.com/forums/showpost.php?p=315636&postcount=42

--dick