Support Group ESA to UC Migration - Incorrectly Asked To Provide Fit Notes

I am severely disabled and this error is causing me a lot of distress. I am migrating from the ESA Support Group to UC. I should be placed in the Limited Capability For Work Related Activities (LCWRA) of UC.
Doing the online migration I was initially told I did NOT need to provide Fit Notes. I accepted the Claimant Commitment - I thought I only needed to do this once having read the guide. I was then asked to accept the Claimant Commitment AGAIN. I thought this was a technical error so I accepted it.
This is what I actually accepted the second time. I have been told I need to provide a Fit Note within 7 days because I have not had a Work Capability Assessment (WCA) . It says I need to keep providing Fit Notes or have a WCA - otherwise I will be deemed fit for work and my benefits stopped!
This is why I think there's been an error. I applied for ESA in 2013. I submitted the form (ESA50?) together with STRONG supporting medical evidence. I did NOT have to physically attend a WCA. The DWP did my WCA based on the form and medical evidence alone. I was then put in the Support Group of ESA. Because I did not physically attend a WCA and the WCA was done on the paperwork this is why this error has occured.
I do NOT need to provide Fit Notes. The problem is I have accepted the Claimant Commitment to do so. What do I need to do so the DWP do not ask for Fit Notes or a WCA and put me in the correct LCWRA Group for UC? Thanks!