OSBORN ROOFING & SIDING CO

I purchased a home that had 30 year fiberglass dimensional shingles put on the roof in the months just before.  4 years later there are leaks everywhere and the shingles are disintegrating.  The seller provided me with pertinent documents and warranties of  various appliances and upgrades, which included the roofing work.  Over the past 13 months I have called about once a month to follow up on my initial call in early 2013.  The old man that  answers the phone says he will have "him (owner?)" call me back.  Never happened.  I have a copy of the contract that was signed by Kenneth Osborn and included a 30 year warranty that covers leaks from "faulty materials or workmanship."  I have been cordial and professional in each call, even pleading for someone to call me back.  Nope.