Kindly note that cancellation after the domain has been successfully renewed is impossible.
Domains registered under Z.com are renewed directly in the registry’s database (upper authority).
In that case, the renewal on the registry’s side will be completed by the time domain renewal is completed, and the receipt of the renewal fee will also be terminated by online service. Therefore, any cancellations or changes of renewal contents are no longer doable.
If you do not wish to renew your domain, ensure that you have off the auto-renew function, so the domain will not automatically renew, nearing its expiration date.
Refer here to disable auto-renew.