If Hong Kong / UK mebbe it's forex trading marketing department? I only receive calls from African countries and recently Papua new guinea. They call you 5 second and hang up. So if I call them back, I get charged like $3/min. I just use an app to block all calls from the African countries

Yeh I used to work as telemarketer during my university summer holiday. Standard chartered outsource their personal loan marketing to the company. Company gives me cold call list of names and contact numbers. Then they instructed me if someone asked me how I get his number, say because he filled up lucky draw or survey forms etc