Hi guys, wanted to share my experience on the same bad luck I'm having with  my external HDD and my experience with Seagate customer service so far.

Device : Seagate Agent Free Go Flex 1TB (warranty expired 2014)
Problem :
Have been using this HDD almost every other day and yesterday, it failed on me (no direct physical damage happened - eg. dropping it, liquid got in, etc). It appears on device manager and the task bar "safely remove hardward and eject media" but DOEST NOT appear on disk management/diskpart

And surprisingly, googling revealed this as quite a common problem (not seagate specific but HDD) and some have manage to fix it by a few different methods proposed on the web. Also, found 1 user who had the exact same issue with me is that, when it is plug it in to my desktop, my PC wont be able to restart or shut down, it just goes to the windows bluescreen.

Attempted solution (aside from googling which didnt work) :
1/ shorlisted a few local companies for data recovery (thanks to reviews and post by forumers) - yet to call them
2/ called up Seagate https://www.seagate.com/as/en/contacts/

Got connected very quickly to a customer service staff. I explained the situation and he recommended :
1/ open up the casing and try to plug it in directly from the internal drive
While still on the phone, I was trying this method with a screwdriver, I could not (without trying to use excessive force)
2/ He mentioned that Seagate would provide a COMPLIMENTARY data recovery service onto a new external HDD FOC.
This includes FOC shipping/logistics to their lab at Netherlands and back  through UPS.
The only thing he mentioned that I might have to pay for is any government tax that might be imposed.
He'll be sending me an email with all the details required and labels required for the UPS logistics.

TAT : expected to take 1 month from UPS picking up my HDD, data recovery and sending back to me

I'm not sure bout you guys......but FOC service with 1 month TAT (considering it's in netherlands) seems like a damn good deal to me.
Will try to update what happens 1 month later

Anyways, hope this sharing helps.

Cheers!