I. Bought a g tec hard drive on the classified forum as a spare that was in June I used it today for the first time and it doesn’t work my tech friend also confirmed this do I have any comeback on this
Might be obvious saying this, but have you tried it on a different computer and see if it has the same issues? Perhaps the USB drivers/controller on your system isn't compatible with the removable HDD.
The thing is, you've had it more than a reasonable amount of time, so if you didn't test it straight away, that's your fault. If you had bought it from a reseller s/h, they would probably have only given you a 3 month warranty - if that. You've had it for around 6 months.
Personally I would never buy a second hand drive. You have no idea how they have been treated. You can buy brand new drives at very reasonable prices.
When in disk Utility, click on the name of the disk (left hand side window) and then go to the icon marked First Aid and click on that (might just need repairing) if that does not work then go back and click on it again (left window) and then click erase.
Have you got show all drives on desktop ticked (finder preferences) this allows you to see drive connected to your Mac.
In my earliest years of having a PC at home (over 25 years ago), I had 2 separate Seagate drives that each failed within a month of their warantee expiring. Even though they were brought new Seagate were completely unhelpful.
I've never brought another seagate drive either at home or at work, and strangely have never had another drive failure.
Devices such as this should be tested on delivery. If it stopped working a week after delivery you MIGHT have some comeback but couldn't be confident of it. Six months later I'd say not a chance. Your best bet is that your techno-savvy friend isn't savvy enough.