Ive been visited by an high court enforcement officer !!!?

been visited by a high court enforcement officer claiming an amount owed of �7000 for a company that has been pestering me for 3 yrs now!! this goes back to 2003 when i went to court with a company origly chasing me for a disputed amount of money owed which got chucked out of court!!! then in 2007 this new company showed up called motormile saying i owed them the debt!!! i asked them for proof of which nothing happened for ages !! after threatning letters and phone calls i told them i would go to the police they finanly went away , however today the officer called demanding the full amount he had full id and relavant paperwork he had no county court judgement and i had to make a payment to agree to installments until i see a solicotor to get it set a side was his advice !! he seemed genuine but cant help thinking what to do next !! any thought or advice out there? as i said we recieved no court dates or paperwork of judgements!! so im wondering are they pulling a fast one!!!! please help !!! thanx andy