It's like smerf said, if it is not recognised, you are out of luck. It may well be that the CF card became slower by being used, now being incompatible with the Amiga.
Nevertheless,
- make sure that the CF card and all cables are connected correctly and properly
- make sure that there is no short circuit anywhere
- make sure that HDToolbox is configured correctly (either SCSI_DEVICE_NAME=scsi.device or nothing at all).
If it's still not recognised, try another CF card or a 2.5" HDD, just to be sure that the Amiga's IDE port still works at all.
