My Mother Has Chronic Back Pain Due To A Botched

My mother has chronic back pain due to a botched medical procedure from Kaiser. She has taken pain medication for 15 years, they recently demanded a drug test and said they would withhold medication until she did. She did and they said they found a small amount of vicoden in her system. They are now telling her that they are going to withhold/ deny her medication because "their test are never wrong".