Hi Cath
Have you received a migration notice?
If you have then I would contact UC helpline: 0800 328 5644/5646/9344 and ask the question, you could also contact Citizen Advice help to claim, you can contact an adviser through their free Help to Claim phone service: England 0800 144 8 444. Advisers are available 8am to 6pm, Monday to Friday.
Gary
Nothing on this board constitutes legal advice - always consult a professional about specific problems