OP, I don't think IB cancelled your ticket, bur rather your flight? So they don't refund your ticket but have to get you to the destination, eventually, at no extra cost to you.
So then question is if for example IB can only offer a fight two days later but one needs to arrive next day latest and there's alternative transport to get that done, would IB cover those costs and do you need tell/ask for approval beforehand to increase the odds of IB paying?