hinder or prevent (the efforts, plans, or desires) of; "What ultimately frustrated every challenger was Ruth's amazing September surge"; "foil your opponent"
To bilk someone out of something, especially money, means to cheat them out of it. They are charged with bilking investors out of millions of dollars. = cheat. to cheat someone, especially by taking their money = swindle bilk sb out of sth (Perhaps from balk)