first numbers: Yeah, as I said in OP, I am aware of this and will not fall for it again.

Hang up immmediately: Why not have some fun and waste the scammers time?

Block and report: Probably pointless as these scammers are likely to spoof their number anyway. Case in point, a relative got a scam call from his bank yesterday and the number was indeed registered as belonging to the bank.

Tell the bank: Yeah, maybe. Next time I see them. 

 The report function least reports back to Google (if you have an android phone) that this call/voip connection is bad somehow.