If you applied for this online then it will most likely have have had a 'tick box' to comply with the CCA.
How has a £30 kettle more than trebled in size?
I wouldn't even begin to entertain this shower with CCA requests, simply tell them that you dispute their eroneous claim that you owe this money, which you don't! Tell them to remove all data they have incorrectly placed on your credit file immediately, if they fail to do so, you will seek legal advice with a view to taking them to court and suing for damages (£1,000 minimum!)
Get in touch with the Credit Ref Agency (CRA) and tell them to remove this adverse data from your file, as you have no knowledge of this company, have never given them your permission to place info on your file and do not owe anyone anything, you will need to use their complaints procedure and exhaust it unless they see the error of their shady ways and remove the info, but be warned, CRA's are on the payroll of DCA's they are like the terrible twins, colluding with each other with scant regard for peoples personal information, you will need to escalate this to the ICO to investigate, a complaint to your local MP also might help to bring this to the fore in Parliament.
Next is to get back in touch with Littlewoods and use their complaints procedure, tell them to call their chosen DCA puppet off, and to cancel any such agreement they thought existed between you and them, the Kettle you bought from them was not fit for purpose and failed after two weeks as the plastic base melted, you will be very happy to take legal action against them and sue for damages, as this matter falls under the Sale of Goods Act, their continued failure to collect the faulty item is not your problem, once again they have failed to show a reasonable level of care and skill in their dealings with you.
If they fail to cut their losses, then they should put up or shut up, your not paying for a piece of melted plastic which they failed to competently collect on a number of occasions, you have therefore purchased another item which is still working after two weeks, unless they wish to reimburse you for the new kettle, then they should tell these fools to remove all adverse info from your CRF before you take legal action against ALL three, Littlewoods, Phoenix and the CRA.