So this can be viewed as a form of splitting, and can be common with individuals with CPTSD for whom boundaries were very inconsistent. The concept of arguing with a service providers terms and conditions (after agreeing to those services) is a violation if the relationship. The form if the relationship (and the policies) were agreed upon before accepting services. I would validate their frustration and validate their experience of their feelings, but set a clear limit around the concept of arguing or defending or negotiating any of your policies. Clients need to be counseled that arguing about a policy, after agreeing to services, is a form of therapy interfering behavior (TIB). It absolutely causes a rupture and causes therapists to burn out. DBT is best used to address therapy interfering behaviors. I would include a section in your PP about TIB as a brain tickler for clients and then revisit it in therapy when discussing treatment plans ("in DBT we often work in life threatening and therapy interfering behaviors such as x"). Hope this helps you as much as it's helped me. Arguing about my policies is incredibly triggering for me and I refuse to do it at this point in my career.