Definitely talk to your doctor and explain the circumstances, who ever is your immediate care provider should be able to either write a note as proof or some other such thing to the detox center or find an even better one that will suite your needs regardless of if you're an MMJ patient!

I'm sorry you where treated that way, a detox center should be looking to HELP you with any addiction problems you have with proof of need for MMJ. A true "health" center won't turn those who are actively trying to better themselves and live healthier lives away. I think you're better off going through a different detox!