Why was I allowed to "Commit to Buy" and only then informed that the seller will not post to my Post Office address?

[teeskware3]

I have just hit the "Commit to Buy" buttons on two items from the same seller.
As I went through the "Pay Now" procedure I was notified with a warning icon that this seller will not post to my Post Office box number.

I sent a message to the seller to explain that because of my geographically isolated rural location I have no postal address other than the official Post Office where I have to travel to collect my mail.

The seller replied, (quote) "So sorry about that  we dont use P.O box.  And because of ebay system . we just can use this shipping method." (end quote.)

This is of no help to me at all.
So, I am now committed to buy the items......right?

[*sparklz* · Accepted solution]

Not sure how the ebay system will not allow postage to a PO box when any other seller can.

PO boxes is the best way for sellers to post items too as they can not be stolen if left at a residence.

Is there anywhere in the listing that sates no PO Box addresses?