Telephone calls are just like emails from people you don't know. Don't answer the call; let it go to voicemail. If it's important the caller may leave a message. If the calls are bothering you at night, turn on your privacy/quiet time options. Don't have a smart phone that can do this, make the decision to upgrade to one.
Newer android releases and phones have all sorts of privacy settings. No caller ID, straight to voicemail. Only allow calls from people in your contact list. Quiet times when calls and notifications are muted or silenced.
Phones are public communication devices and people who are not engaged in deliberate and protracted harassment are free to call you as often as they want even at 3:30 am if they so choose. It's up to you to unplug, turn off or implement some other method of limiting annoyances and distractions.
If you feel that you are being harassed, you can file a report with your cell carrier. They have the records of who called you, when, and if there is a clear pattern of abuse, they can put a stop to it, if they want to.
The police will just laugh at you and ask for 200.00 pesos for occupying space standing front of them.