These people are not legitimate. I don't know where they got my unlisted phone number, but their persistent calls indicate that something is not right with them.
Yesterday I received a call from these fools. The guy was very persistent when I told him I don't donate to random calls and before I do, I want to check them out. He kept going on, so I hung up and immediately blocked the number.
Got the call today informing me that the call is being monitored etc and that they are conducting some sort of charity work etc. and he belong to a police organization. They are calling my home numbers. Hung him up!!!