Broken Cartrige Guide Arm, can't find part number

Canon ImageClass D320

The "Cartrige Guide Arm" is broken but I cannot find the part to order and replace it.

It's a small white plastic piece that the S35 Cartridge fits into and then is slid into place as you close the door/hatch.

Someone must have broken it as the forcefully removed the previous Cartridge now that I have a new cartridge it won't slide into place without this piece.

Thanks,
Alex