Mackenzie Hall Default on Credit File?

gwilo

I recently got turned down for car finance and, even though I've changed address quite a bit and not had much of a credit file, I thought I would join Experian and have a look at exactly how my credit file stands and try and clean it up/build it up. Anyway, it appears a few things do need cleaning up/looking into but one thing did jump out as a major issue. There is a default on my file put there by a Mackenzie Hall (yes I've read a bit about them on this forum) to the tune of £900. It's accredited to 'Mail Order'? Now I know for a fact that I've never had anything by Mail Order or ever had a catalogue, which I'm assuming is what it means. My question is, how do I approach it? Do I send them a 'prove it' letter asking for details/proof and for the default to be removed? I'm conscious of opening up the flood gates to endless letters and hassle (after reading this forum about this company) but I don't know how else to play it. I certainly won't be dealing with them via phone anyway. Any advice would be welcome.