Ask for head of household twice and then hung up, sounded like an automated system.

Called and hung up.  When I tried calling back there is just a busy signal.

It's their second time calling. The first time I didn't answer, which was yesterday. Today, I did and they asked to speak to my mom or dad. I asked who they were calling for and they said "Can I speak to the head of the household please?"

I hung up. I'm pretty sure it has to do with that stupid prank calling app or whatever people are doing these days.

I called the number back and it went to voicemail saying that it's a Fundraising company."

Called, asked for head of household, when I asked who was calling, the woman said that there "is no message" and hung up. Blocked the number on my phone.

It's a fund raising firm.  I have no idea for what though.