MicroSD card - WINDOWS CANNOT FORMAT THIS DRIVE

Ive been using a SanDisk 64GB Mobile Ultra MicroSDXC Class 10 Memory Card with my Lumia 1520 for the last year with little to no problems, then last week the phone can no longer save photos to the camera roll on the card. I've tried all of teh trouble shooting I can, and have made a copy of the sd cards contents onto my pc.

However, I cannot format this card using any method.

I have tried each step listed here but am still unable to clear this card and reuse. In fact after seemingly deleting everything from the device, viewing the card in file explorer and it appears to be empty. then slowly all of the data reappears when the card is reinserted into the phone. any help or is this card done?

Is there a little write protect switch on the side of the card? If yes has it accidentally been set to write protect? Can you format it in diskpart?

The card is not locked. Nothing is working. Diskpart, attributes disk clear readonly AND "CHKDSK X: /F" did not work.

I'd say the card has failed, it happens.