Replacement of internal drive for My Book Thunderbolt Duo Dual with RAID

Where or How can buy a replacement of an internal drive for My Book Thunderbolt Duo Dual High-Speed Storage with RAID?
I live in Canada, province of Quebec.
Thank you

You can try this website https://www.wd.com/en-ie/products/internal-storage.html
or call WD support in Canada to order hard drives.