Caller ID showed this number and "Unknown Name". When will people learn that if they don't show who they are in Caller ID people won't take their calls?
This is a medical research company called suAzio. They do studies and research projects all the time on new developments in the medical industry. I just did one on a neonatal MRI which was really interesting. They often to compensated studies and they do pay every time, it just takes a while sometimes. In order to get on their lists for interesting projects you can try participating in one of the short customer satisfactione ones. Calling back is no use as it is a Belgian number.