Dietician Stating They Won’t Send Prescription To Other Dme

Hi, looking for advice regarding my daughter’s enteral feeding supplies. We live in Washington state and she has Medicaid. We are needing to try a higher calorie content food that is available from a specific manufacturer that her current DME does not carry. The dietician told me that we are not allowed to get food from a different DME and keep her other food and supplies with the current one, it’s all or nothing. So, she is stating we would have to switch her DME entirely if we want to try this food because the current DME (which happens to be the same place she works) does not allow you to get enteral supplies through them if you don’t get food through them. I understand this is because they feel this is how they make their money. The dietician stated the insurance company does not care if you use multiple suppliers, this is entirely a policy of the current DME. Is this even legal? I asked if she could give me a written prescription and I could take it to the supplier directly and she refused. I’m not sure how they can force us to only use their company for all supplies or I have to switch entirely. The other problem is that the suppliers that do carry the food we want to trial do not carry the other food that we are currently mixing it with. She is stating we would have to pay out of pocket if we want to use a different company. I just really don’t understand how that can be legal. Any thoughts? Thanks in advance!

Location: Washington State