The first thing you might want to do is address your ice damn problem before it become serious.

THE HEAT SEEPING INTO THE ATTIC DUE TO INSUFFICIENT INSULATION OF DUCTS IS PART OF THE ICE DAMMING PROBLEM.

Sorry to be cranky but could we stick to the questions that were asked please.

Not with that attitude.

Blown in or in this case blown over cellulose is not how to insulate ducts. You may have got R50 for the ceiling though.

If the contract said it was to insulate ducts you were taken. If all you got was tape on your ducts to seal them, and not a duct sealing mastic, once again taken.

Calm down, and yes leaking uninsulated ducts in cold climates will thaw snow down to the overhangs and other cold areas and cause the ice damming.

What specifically should I ask for to fix the situation? How are ducts usually insulated in an attic? What specific materials? I want to be able to say specifically what it is I want before I speak to them. Thank you.

Dusts are typically sealed with a grey duct sealing mastic brushed on over the cracks. There is an aluminum tape (not dust tape) for the DIY and lazy that does work fairly well.

For the insulation a foil faced duct wrap or board is applied to the desired thickness and sealed with special tape either self adhesive or bonded with a heat iron.