Called no one on the other end - blocked now

Caller ID:  UNASSIGNED.  I answered this call with my usual business greeting but no one said anything...line was open for about 10 seconds, then call disconnected.

Patiently endured several hang-ups from this number in order to talk to someone.  Caller said he is from Funding Source and that my business is eligible for working capital.  He wanted to ask questions about my company, but I asked if he would please call me back another time, which he agreed to do.