Hold onto boarding passes, even AFTER miles have been credited
While I am sure most FT's routainly retain boarding passed until miles are correctly posted, I have been making it a habit to keep them for a couple months AFTER they have been posted, as their are reports of "disappearing" miles. Do you really want to explain/argue in circles with a near powerless overseas based CSR, or just simply fax/scan the boarding passes and let them speak for themselves.