Calls multiple times per day, modem call

calls received at midnight, 2 am, 4 am and 6 am.   Didn't answer because it's not the first time the harrassment has happened.  One call went to my voice mail and it's a fax pinging sound.  What's the point of this?  Where is their enjoyment?  What do they gain?  It's ridiculous!

calls at 1:26am and 1:55am

Got calls 11:01 11:19 11:38 11:59pm. How do you make them stop?

Just switched from verizon to comcast and these calls started.  Middle of the night, all througout the day (3 so far today)
message is a series of modem type beeps