If an interpreter is not a member of RID, you cannot file a complaint against them through RID’s EPS. You may want to discuss the problem with the interpreter, and if that is not successful, consider talking to the employing entity that contracted or arranged for the interpreting service.
RID’s purpose is to serve equally our members, profession, and the public by promoting and advocating for qualified and effective interpreters in all spaces where intersectional diverse Deaf lives are impacted.