Urgent advice needed about Cabot ccj claim please help

[Greg1801]

Hello I received a ccj claim and have requested the relevant documents to make my defence however I received a letter telling me to write to the court to extend deadline by a further 28 days which I did. Then went on holiday when I got back I sent another letter to the claimant solicitor (Cabot) and they sent me another letter yesterday to tell me that they don't hold the documents I requested and Cabot can't find them as yet so they are putting it all on hold until they can get the relevant documents... now my defence has to be in by Tuesday the 25th July so what should I do... how do I go about putting in a debt I don't have any recollection of as it was over 10 years ago many thanks