That's not true. It could be the fan, or it could be the hub. I don't see enough information here to make that determination. Do other fans connected to the hub, if there are any, work? Have you tried connecting the fan to one of the motherboard headers instead of the fan hub, to see if the fan works that way? If the fan does not work connected to the fan hub OR to any of the motherboard headers, then the fan is probably dead, but if the fan came with an adapter for use with a four pin Molex directly from the power supply, that is an additional method you can use to test the fan operation as well.
If it doesn't work like that either, then the fan is definitely dead. I've seen problems in the fan control circuit on motherboards cause all of the case/system fan headers to not work, but not affect the CPU fan header at all. Is your fan hub connected to a case fan header or the CPU fan header? I've also seen corrupted bios shut down the fan controls in the bios settings, so that none of the fans worked or worked erratically, so double checking the settings in the bios and/or updating/reinstalling the bios firmware is always an option in a case like that.
Just a few other things to check anyhow. Basroil is probably right, but I wouldn't immediately condemn the fan without verification first.