I used your sponsored link on Amazon to find a toner cartridge for a Brother HL-L5100DN printer. Entering company and type, you supplied a dropdown list which included L5100 but not L5100DN. The cartridges you offered for L5100 did not include the one I thought was correct. Perhaps you could do with updating your model list; a subsequent search on your site for that specific cartridge (TN-3480) revealed that you could have sold it to me.
10 November 2017