How can I find a healthcare provider who treats rls?

Sleep center. No one seems to be responding to you. Restless legs is a very common disorder. It is now being treated by sleep centers. A sleep study can determine how serious it is, and then treatment can be recommended. Have your primary doctor refer you to a sleep center covered by your insurance.
Ask. Most primary care doctors are able to treat this, but it wont hurt to ask before and confirm they manage this condition.