Hi Colin
I'm sorry to hear that your health has deteriorated. It is standard practice that when a claimant reports a change of circumstances as you have done, they do a reassessment - which can be telephone, video, face-to-face or paper-based. When you returned the form, did you also send in any additional evidence and explain the impact of the changes as related to the PIP criteria? If you feel you did, you could ask them to do a paper-based assessment. Unfortunately, they don't have to agree, but it's worth putting in the request. If they refuse you can appeal a second time, but after that, you would have to accept their decision.
BIS
Nothing on this board constitutes legal advice - always consult a professional about specific problems