warranty claim not honored

I fitted new set of Dunlop tyres at Aero city wheel and tyre on the 17th of Feb 2015, and yesterday the 16 of March 2015 I spotted one tyre having a side wall bubble, I took the car to Aero city, they striped the tyre from the rim and get it checked, they assumed that I hit a pothole, but they didn't find a substantial damage that can result from a potholes. They referred to the manufacture as the carry the warranty. Today on the 17th of March 2015 i took the car in at Dunlop jet park, they stripped the tyre from the rim and what they did was a \PHYSICAL CHECK"on the tyre NO machinery was used to check if it was a manufacture fault or not"