After reading Yuga's post, I became more certain that something went wrong with a carrier's prepaid reloading system.
I made an e-load to my prepaid mobile number last October 2 (8:00 pm) in the amount of P150. The next day, was trying to use my phone to send a text and call but got a message that I have no enough credits left.
In this situation, it feels helpless being a prepaid user with no logs to check or turn to. In times of crisis, the infrastructure must be stable to avoid glitches like this.
I do hope that NTC and DTI's Order on Data Log Retention and Consumer Protection in Products and Services provided by Public Telecommunication Entities will be out soon.