I don't know what these people want they never leave a message or say anything, who are they?

This is a company based out of Israel called HebrewOnline.  They may either have a wrong number or you may have inquired about a hebrew or chinese language course and this is how they got your number.  They are very nice and if you ask to be taken off their calling list, they will courteously comply.  Hope this helped :)

12 calls in 3 days. Two of which were before 6 am. No messages.

If you looked into learning Hebrew and filled out the information with Hebrew Online, they are calling. I told them I would prefer to correspond via email. Done! They are very courteous and polite.