Called my personal line. Gave them as many "No" or "not saying" answers as I reasonably could. Of course, there is little I can do about it as they are outside Europe. The missing country code on the caller ID was typical of these calls. Called at 18:44 UTC. They're going on the redlist!
This number has called several times in 2 weeks. When I answer, there is no reply. Also called my 90 year old father which is a great nuisance and worry to him. Suspect this may be the same as one call I managed to answer which purported to be a 'survey'.