When I was in Japan, I had an account with DOCOMO (local cellphone service). I used the number frequently delivery services, bank services, hotels, etc. I never received a single unwanted phone call.

I return to USA I get new cellphone service and same day I get dozens of unwanted calls and immediately have to block all numbers not in my contact list.

Since the problem of unwanted calls doesn't exist in some countries, I have to assume that it is a solvable problem. Countries where it is a problem simply don't wish to solve it. I suspect it is simply some countries favoring corporations over individuals.

I had't had one in 12 months in the UK. It's time to renew my car insurance and I entered my number for a quote into one of the major providers websites, and I've had 3 in the last week. I hate to make assumptions, but it's just too coincidental.

It’s better now the PPI crap is over but I get plenty on our business line from robots claiming to be BT, HMRC, and Amazon.