Ignore.
They sent you a Letter of Claim, you replied. Job done.
Save your energy for writing a defence to the county court claim, which should address their Particulars of Claim (on their claim form, which you haven't received yet) and specific defence points applicable to your situation.
DCB Legal have a familiar process in which they almost always discontinue before having to pay the court fee, because their clients don't want to pay the fee and, more significantly, for someone to attend court. So you follow the process, get the case allocated to a court local to you for a hearing in person, and don't miss any deadlines along the way.