Help with opiate addiction?

My stepdaughter has a nasty opiate/benzo addiction problem. She has 100's of tricks for getting drugs and is becoming increasingly difficult to live with - stealing, lying, breaking into everything. My house has been gutted for her to sell things to satisfy her drug addiction. It's driving me nuts.

I need some ideas. Facts:

1) Mom won't let me call the police on her. I think this is stupid but Mom hates police and is worried that it will destroy whatever relationship she has with her daughter. I can't change this. Really.

2) She won't go to residential treatment (she is 26).

3) She would go to NA meetings but as near as I can tell NA is a fiction. I've tried to take her to meeting after meeting and have been told repeatedly that "We cancelled these meetings 6 months ago due to lack of interest".

4) Every time I take her to some doctor, it backfires when she tells them about some odd malady and doctor hospitalizes her or prescribes her opiates. Either way she gets her opiates. For instance, last month I took her to a doctor specializing in drug addiction and within a month he had prescribed 90 mg/day of oxycodone. This kid has literally been diagnosed with 20 fatal diseases and spent $400K on medical tests just so she can get high.

I can't live this way and it is driving me (and my son) crazy.

TIA.