As already suggested, try using another cable that you know works or try the drive in a different computer. It could also be the power supply if it uses and external power cable. Failing that contact the manufacturers tech support for advice as they know their products are are best placed to advise what to do next. If they cant help then the local pc shop may be able to recover the data. If it’s the drive itself, then perform an internet search for ‘data recovery perth’ for specialists that perform this service. Note that this can sometimes be quite expensive so you may want to enquire how much it’s going to cost.

Hard drives on a pc or external drives need to be viewed as consumables. Sooner or later they will fail. I span my pc backups over 3 removable drives. Overkill maybe, but the $500 cost in drives is cheaper than the trying to retrieve 20 years of accumulated data in the event of failure/fire/flood/theft/other disaster. Distributing my data over multiple devices stored in multiple locations distributes my risk. I keep one at home, one at work and one in my bag that I carry to work and all are password protected in case they get lost.

As for optical media (CD, DVD, BR) this can also have issues. The media itself my last a long time but I have encountered users who have had problems reading the media back. I suspect that this is a function of the drive doing the burning/reading and in some cases the media itself. Some drives just don’t like some brands of media. Often these drives are cheapest component on a computer with quality to match. If the media is not burned accurately then reading the data back may be problematic. If I am burning to optical media I take the disk to another computer with a different drive and confirm I can read the information off the disc.