I See A Pain Clinic Doctor That Gives Me Dilaudid

I see a pain clinic doctor that gives me dilaudid and soma for pain I also see a doctor that gives me Xanax and Seroquel for depression I have seen this doctor for years and never had a problem he give me a urine drug test on me like he always does I just got a call from them and they said that herion showed up in my urine test and they can not see me anymore I have never in my life ever done any type of drugs at all what can I do? I would never do anything like that because I need to continue to see my pain doctor I have had 3 back surgeries 2 neck surgeries and was in a real bad car wreck and I am disabled please tell me what to do because they have made a big mistake at the drug screening place.