The Kimsufi line is a bunch of low-end boxes not meant for serious work, they technically allocate every server a /64 but you can't add RDNS records for anything but the "/128" you've been allocated.
If you want a proper /64 block and support for it you need to get a server from their SoYouStart or OVH branded offerings.
If you want a proper /64 block and support for it you need to get a server from their SoYouStart or OVH branded offerings.