As Scooter said, bentonite is a great clearing agent, and a little hard to get into suspension. When I use it, adding it slowly, while stirring, to a cup of boiling hot water has always done the trick for me. Bentonite is only one half of my protocol in a wine that won't clear, the other half is chitosan, it's a thick liquid and mixes in pretty easily. Together, they effectively remove charged particles as well as protein haze from your wine.
If you have a pectin haze problem, pectic enzyme is the answer to that problem. Before trying the bentonite or bentonite / chitosan combo, consider trying another dose or two of pectic enzyme, it's easy to apply, you can't really use too much, and it'll work very quickly once the dosage is sufficient. Additionally, it sounds like you already have some on hand.