I believe payment by a cashier's check is a well-accepted method of payment with big ticket items. ignoring all the downsides of fake checks.
I believe its possible to have a stop payment issued on a cashier's check, but the check cannot have been presented, and reimbursement of the check will not take place for an extended period of time, like up to a year.
So, one considered safe way to deliver a cashier's check is thru USPS. If sending Express Priority mail at a cost of over $30, normally it's delivery is guaranteed by next day, and tracking is part of the service.
What is the fly in the ointment and seldom mentioned, if your envelope with a big cashier's check enclosed is not deliverable for any reason, as determined by USPS, it is returned via regular mail, with no tracking.
Ouch.

Note if address is a PO Box, only the USPS can deliver it.