Just thread an M5 bolt into what is left of the tee-nut and then pund on the head of the bolt from the bottom of the boot and the tee nut will pop out into the boot. I have done this on mine before. Then get some new Intec heels that will come with new tee nuts and get new stainless bolts the onces that come with the Intec aparently are not stainless. If your bolts have corroded I bet it's time for new heels anyway. The bolts are M5 x 20mm phillips BTW and I think you can get them at your local ACE. If not, they are part numer 92000A328 at www.mcmaster.com.
Usually, the deformation that you see is the head of the tee-nut that has been bent by slowly tighening of the bolt over the the years. New heels, new tee-nuts and new bolts and you'll be all set.
->Ben