The reason large companies often call using these numbers that are 'blocked' are often just simply company policies and are done for safety reasons to the employees. I have experienced this in my own line of work and there have been cases were some crazy customers have treatened individuals calling them. So in order to ensure the safety of their employees companies block their numbers. They are not 'pranking' or 'scamming' they just have to do it as a safety measure.
This number called me for about a week (one call/day) and never left a message. Finally was around when they called; turned out it was Honda calling to ask me if I wanted to do a survey about my new CRV I just bought. I told them no and to never call me again and now the calls stopped.