I have no idea how that could happen, but I really wish you would have demanded a blood test. I was a .26 my first dui and was reeaaally wasted...I have heard that certain things like mouthwash and breath mints can cause breathalizers to give false readings.....but a .27!!!!!
I don't know what to tell you sir, but if it was me and I knew I hadn't been drinking but blew a .27 I would still be in jail for swinging on everybody for false arrest. Something is goofed up here, keep looking for a lawyer is all I can suggest.