Dell knows there switch is broken but they still ship it do you know why

I have just got a 5548 switch and from the day I installed it in my clients network their supports calls to me went from 2 a week to over ten a day , after a month I found the switch was the issue in the log it would say port down / port up the port were dropping off an online so I called dell and they said it was a know issues (if it was why sell <removed by admin> that don't work) and all I had to do was turn green either-net off but that did nothing so they sent me a new switch as it must be the faulty switch as turning off green either-net should of fixed my issue but guess what it did noting the new switch has the same issue as the first switch all port dropping off and online and the firmware can not be updated on both switches I downloaded the firmware and when I upload the boot file the switch will not accept it and when I up load the image file it uploads but right and then end its say's illegal file format (which is the file dell has on their site) so I dont want to leave a currupt file on the switch so I go to delete using the consol but I can not I can delete and copy any file on the switch but not image-2 the firmware the switch said was illegal file format . I can not dell will sell a product that they Know is broken there server engineers told me its a know issue for the switch to drop port on and offline we are not talking about some feature not working we are talking about its main function a network switch. I have been on the phone to dell again this morning and after 40 mins on the phone I was told to send the tech-support command out out to then and a email explaining my issue which I have to them on the phone already.

So dose any one know how to get a power-connect 5548 to work with out dropping in and out. 

And two If I sold something to some one and I new it would not work as advertised I would be charged with fraud why can dell sell product they know don't work (their on engineers told me its a know issue for there last two firmware version)  and get away with it any one else would be dragged before a court for fraud.