Is the appointee of a claim meant to get any correspondence or the claimant?

Good afternoon, I was made the appointee of a PIP claim some time ago and up until recently all correspondence have been sent to me. However, I recently informed PIP of a change of condition. However, on waiting for correspondence regarding any updates it has come to my attention they have sent recent correspondence to the the claimant (the person I am appointee of) rather than addressed it to the appointee. After being on hold for a considerable amount of time the phone line cut out so I didn't get to speak with an advisor. I have always been of the understanding that all correspondence are sent to the appointee and not the claimant—can anyone confirm who is meant to receive the letters/updates?