How to restore posts after deleting an account
If an account had scheduled posts and the account was deleted, all associated content is also deleted from the service. However, if a post is scheduled for multiple accounts, for example, A and B, and you have deleted only account A, the post will remain in the system. It will be permanently deleted only if you also delete account B.
If you want to restore access to these posts and continue using them, this can be done through customer support (they will restore your deleted account).
What to do
Contact the service's customer support and indicate which account was deleted.
After restoring the account, the posts will reappear in the system, and you can, for example, move them to another working account.