this number has contacted me literaly over 50 times in 2 days and when i try to cll them back or answer the call it gives me a dial-up sound, who does this number belong to?

I keep getting dozens of calls from this number all day and all night. It wakes me up at night. When i pick up i has a fax ring tone. Help!

This number calls at varies times and when you answer it's only beeping. If you call it back the line is just dead silence.  I'm not in debt or collections so I shouldn't be harassed etc.