You can send Certified w/Return Receipt mail to a PO BOX;they either have couriers that retrieve their mail from local station or it's delivered to them by the postal carrier. Sister Girl P.S.---I use this service all of the time & I send to PO Boxes w/return receipt signed & dated.
I HAVE CLOSED MANY CREDIT CARDS...I ALWAYS TYPE A CLOSE LETTER AND TAPE THE CREDIT CARD TO THE LETTER AT THE BOTTOM AND SEND CERTIFIED R/R... I KEEP A COPY OF THE LETTER FOR FUTURE USE IF NECESSARY... NONE HAVE EVER HAD A STREET ADDRESS...ONLY PO BOXES.