Stop spam calls

When I answer there is no-one there, When I ring it back there is a loud screeching sound then the call is cut off.

Called, From,'windows', Claiming, My, Comp, Is, Hacked, And, Is, Going, To, Help? Scammer.

I have received repeated calls from this number. There is delay in them speaking which suggests they are using automated dialing

Called from "UK Benefit" about life insurance. When queried about who UK benefit were (asked for company name and Co Reg No) and how they got my details the caller hung up. Unsolicited marketing of financial services..

Rude pest caller