canceling my sab will delete my fills ?
No.
If you cancel your paid subscription you will be dropped down to the personal(free) tier, and your account will have the limitations that come with that (see comparison), a big one being you can only have 3 projects, so any additional projects you have will still remain but will be locked for editing.
If you want to completley kill your account then head over to the delete area, which will remove all your projects and data.