Hi, welcome to Just Answer. I will help you with your question.
Have you seen the claim form that was issued against you? And if so, does it have your correct address on it?
Basically, you can apply to set the judgment aside if you've never received the claim for.
You would make the application on Form N244 and lodge it in the county county explaining that you've never received the claim form and that you have a defence and you should state what that defence is. The Court will then call a hearing to determine whether your judgment should be set aside.