I keep getting calls from this number but when I answer there is no one there so I think it is a robo call, When you call back they say the number  is disconnected.  I assume it is just another scam trying to get access to my computer or sell me something.

Report this scammer:  https://www.treasury.gov/tigta/contact_report_scam.shtml

They threatened that if I didn't call back something bad would happen.

Yup, something bad would happen, they wouldn't be able to con you. Bullet dodged.

Got a call from that number and when I called back it went to a busy signal