https://www.theverge.com/2017/8/23/16189724/samsung-galaxy-note-7-discounts-note-8-unpacked-2017 notes a hefty 400+ USD discount so your warranty will likely only covered the discounted price if you go for accident insurance. I could be wrong.

Anyhow, insurance could be available from any company that wishes to get into that. (Legal requirements of course.)

So you have to shop where you can and the insurance should seen OVERSIZED given the discount. I can see where insurance may be just as much as the discounted phone.

PS. Added with edit. Insurance may seem high due to the discounted price of the phone but what I saw looks same price as what the full price phone insurance is.