I am getting the same here! They call about 3 times per day or some times more. When you call back it sounds busy, then it tell you they number has been disconnected or is not in service.
The caller is a cruise scammer who keeps calling both my cell phones from different numbers (or fake caller IDs), always from the state of Washington. I've come to recognize the calls just from the steamship horn, before the robocaller even can claim to be my Captain. I block each number as the calls come in, but the crook seems to keep changing numbers just to circumvent call blocking.
Robo-telemarketing calls to cell phones are illegal, so I'm assuming the outfit making them is crooked.