I live in Belgium. I receive such a call on average twice a (week) day. Sometimes it's just blank call (nobody answers) sometimes they're offering gifts if I go

I live in Belgium. I receive such a call on average twice a (week) day. Sometimes it's just blank call (nobody answers) sometimes they're offering gifts if I go to shop X, they ask if I want to compare my phone/energy bill. The funniest one is when my fixed line provider (let's call it P) calls me on my mobile phone (which is another provider) and ask me if I'm one oh their (P) customer :-) (the explanation is that the mobile/fixed businesses are separated to avoid monopoly and, since they can't share customer data ('cos of data protection rules), they have to ask them again :-))