Can a pain doctor suddenly stop your pain medicine? ?

My pain management dr wrote me my regular pain medicine and started me back on my ADHD medicine yesterday. After I dropped it off the pharmacy called saying someone had filled a script on Nov. 12th with my name on it from another dr so therefore they called my pain dr & he said since it was a breech of my pain contract he had canceled the ENTIRE prescription including my regular pain meds. I have a torn disc and have been taking my prescribed pain medicine for years. I did not get a script filled on that day and I'm trying desperately to prove this but I'm worried to death that I'm going to be sick as a dog & in horrible pain within days. Not to mention with the meds he prescribed I could go I to cardiac arrest & die if they aren't weened down. If my name isn't the one that picked it up from the pharmacy & I didn't go to the dr on that day, (they said they had given the script to someone but doesn't know there name) how can this dr just suddenly stop my medicine, ESP if this wasn't my fault??