I had the same issue. Numerous people tried to give my daughter a bottle to no avail. My problem was that she took a bottle and then I slacked off and just nursed her. She wouldn't go back to the bottle.
They recommend you find someone experienced with getting a baby to take a bottle. I was so stressed out on my daughters first day of daycare because she would not take a bottle. My experienced sweet daycare mom knew how to make it happen... patience, distractions, take a break and go back to it. It took her about 1 1/2 hours, but my daughter finally did it. That was it and she took the bottle from that point on.