@Kiram_Tursun See the discussion in this thread:
https://answers.netlify.com/t/lease-delete-site-starlit-kitsune-d4a196-netlify-app-i-lost-access/147010
Netlify don’t delete sites just because people ask them to, you would need to prove ownership of the site, (which you may have no way of doing).
If the site has been created into Bolt’s account, then Bolt will need to delete it.
If you’ve deleted it in Bolt, and they failed to delete it on Netlify, then you should raise the issue with Bolt.
If enough people raise it with them, maybe they’ll fix it.
Their support page is here:
https://support.bolt.new/external-resources