In a bit of Googling the earliest Isband I could find was Isband Goske, who is listed as being a commander of Dutch forces along the Malabar Coast of India
in 1666 and 1667:http://www.worldstatesmen.org/India.htm
It's therefore possible that Isband is a variation of IJsbrand, Izebrand, or Isbrand, which my Dutch name dictionary (Woordenboek van Voornamen
by J. Van
der Schaar) says goes back to Germanic roots that meant "iron sword".
I'm not sure how or when the "r" would have been lost in the name, but perhaps you should look into the possibility that your ancestor originally had some connection with Dutch settlers in New Netherland (now New York