Income Based ESA to UC- massive issue

Any help would be seriously appreciated.
My husband and I moved from Northern Ireland to England last week. We were on income based ESA. We moved to England on the 8th and discovered that when my husband updated our address with ESA the Northern Irish branch didn't transfer our claim to England- they just closed it entirely as of the 7th. I applied for UC on the 9th thinking everything was okay. We got what was supposed to be our last ESA payment when I realised what happened- it was £500 short. I received no letters saying the claim was closed. So it turns out that we applied for universal credit with no active ESA claim. We had a severe disability premium and now I'm not sure we'll even get transitional protection. The English ESA department wasn't sure what to do because the Northern Irish ESA department didn't send them our claim information and the Northern Irish ESA department pretty much told us to kick rocks since we don't live there anymore. Citizen's advice said that this was beyond their scope since they primarily help with universal credit. I'm utterly terrified. I was relying on that final £500 from ESA and we need the severe disability premium with universal credit to survive. I don't know how this could happen. Has anyone seen this before and gotten it fixed? I'm devastated.

Or can I please get advice as to who to contact about this?

Hi David,
Please do ask if you can. That would be an enormous help. I don't know if I misconstrued your previous advice or just got confused in general because I've only talked to citizen's advice in England. I've been seriously overwhelmed. I apologise.

Hi David,
Looking through my old posts I see your advice. I intended to claim universal credit as soon as we moved so I didn't think I needed to consider staying on ESA. That's where my head was at. Clearly my mistake.