Do I really have to pay for this airline ticket twice?

Cebu tail. / Photo by nucksfan604 – Flickr Creative Commons
Question: At the tail end of a trip last year to Southeast Asia, I had a pair of tickets on Cebu Pacific Airways from Singapore to Manila, and then from Manila to Osaka, to connect with my overseas flight back to the States. I bought the tickets separately because Cebu only does point-to-point ticketing.