CF card reads with 50D but not with Mac Pro

[johansugarev]

I have an urgent problem with a CF card of mine, any help would be deeply appreciated.

Camera Make/model: Canon 50D v1.09 (latest)
Card: Komputerbay 32GB 1000x card
Computer Operating system:  OSX 10.9.4
Mac Pro serial number: G8840ZKX5J4
File system being used on camera: FAT32, formatted in camera
Card reader details: Sandisk ImageMate all in one usb 3.0 Card reader, supports UDMA7.
Port used on computer: USB2.0
Serial number from the bottom of the card: FR1306KXM32G TW

The card was used for raw video with the latest magic lantern nightly build and the card runs and preforms 100% in the camera. However when I try it on a computer through a brand new usb3 UDMA7 card reader it doesn't show up anywhere - including disk utility.

Until recently I have used the card with cheap Chinese card readers. I have two no-brand ones which used to work, a Hama usb2 one I bought recently, and since it didn't work, I bought an expensive Sandisk reader with a NEC chipset.
The card still works fine in the camera, I can take pictures and transfer them to the computer when I connect the camera with USB. But the card doesn't show up at all when using any card reader. I have also tried in Windows 7 and 8 - with the same result. The card has been formatted several times in camera - magic lantern has been removed on the last format.

Could it be that I damaged my card with the cheap card readers? Has anyone experienced this? Any tips, is there a way to revive the card, or i should just get a new one?

[walter_schulz]

If you do a search for something like
Komputerbay corrupted
you will find some issues after using non UDMA7 readers.

My case has a label telling me in quite unmisleading terms to use UDMA7 compatible cardreaders only and there is a warning not to do so may damage the card permanently.
I suggest you may contact Komputerbay support.

[johansugarev]

I contacted Komputerbay and they can replace it, but it is going to cost me a lot of time.