Everyday for ages I finally picked up and said hello and 4 seconds later they hang up I tried to call back but no answer

Calling on a regular basis, they don't leave a message, I don't answer

Pretty sure they're either a course provider OR a donation company.

This number has been calling me everyday, twice a day usually at lunch time and around 4pm. I do not answer numbers I don't know and the area code is from Melbourne, i live in Sydney.