I did not answer it.

I got a call from this number too at 7:30 in the morning on my toll-free line (which costs me money of course) and they left a blank message on voicemail.

Same as Nina - call to my toll-free number w blank 4 sec message

Is your tollfree number come from RingCentral ?

I also have these calls sometimes..

We are a game tester training company.  They called and left no message.