IR ESA top up assesment, UC Migration letter

I had written before on this forum regarding that. I had been claiming Esa Contribution Based, Housing Benefit and PIP since 2019.

I have realised that I might be eligible to claim ESA IR top up to my old style contribution based benefit.

I had sent in ESA 3 form together with IS 10. I had couple of phone calls with ESA about that, they were doing financial assesment from the date I first started claiming benefits which was 2028/19. They were giving me calls about that, I also had to submit to them bank statements for all those years, copy of my ID, accounts closing letters, receipts and statements for every transaction over £250 going out from my account. I had to provide them with a lot of information in order for them to let me know whether I qualify for that IR ESA top up or not. And of course backpayment of money.

They told me that I need to send all of this information to them by the 28/10/24, which I did sent it to them.

But today, I don't know if this was planned by them or not. Maybe not, I don't know. I had received Universal Credit Migration Notice. And that I have to apply for Universal Credit by the 25/01/2025 in order to help my housing cost instead of housing benefit.

In this situation I do not know what to do. Obviously on Universal Credit I wouldn't be eligible for IR TOP UP. What does it mean for me and for the top up and backpayment I was hoping for?

As I said I had submitted to them all the evidence they asked me to by the 28/10. And now I received this letter that I need to migrate to Universal Credit by 25/01/2025.

Will they still need to backpay me the money or once I make the application for UC then my chances are gone? I genuinely don't know what to do in this situation.