Worth noting that you can order NSO documents online and have them mailed to you. I have personally used this to obtain a marriage certificate of someone who was being "difficult" about providing documentation I needed.
Apply online through:
NSO Birth Certificates (and more) | Online Application | Worldwide Delivery
Fees were paid at a 711 through some payment option the government has with them.
Documents arrived from Manila after 4-5 days. I was pretty impressed at how easy it was.