Three places, three steps
Your journal is here, your check record is on CageWatchr, and your account is on ClackID. Each is deleted in its own place, so deleting one never surprises you by taking the others.
Your journal
In Settings, Delete everything removes every journal entry, lock and reminder from chastity.report straight away, deletes the check photos you keep, and tells ClackID to forget that you used chastity.report. ClackID checks it is you first; then you have five minutes, and you type delete to confirm.
If you pay for Plus yourself, cancel it first, so nothing bills after your data is gone. Plus from a keyholder or from CW+ does not stop you. Comments you left in someone else's journal stay with their journal, without a link to your account.
CageWatchr and ClackID
Your check record on CageWatchr stays until you delete it there. Your ClackID account stays too; deleting it on ClackID also stops anything billed through it and disconnects CageWatchr.