Number called twice. 2 second blank voicemail the first time, no voicemail the second time

I have been getting calls from this number 3-4 times a day for the past week. I never answer numbers I don't know but am about to block this number, as it's pretty clearly up to no good.

Same experience as Anna.

I get at least 1-2 calls a day from this number. No voicemails being left. When I try to call the number back I get a response that it's not in service.

Another annoying scammer our government and voice service companies do nothing about.   Thankfully there are free robocall blockers that re-route these calls after one ring.  Now this pain in the butt is blocked forever.