help charge on house

harrio

Hi all after some advice I got divorced 7 years ago I instructed a solicitor to represent me after divorce settlement they sent me an invoice I disputed the amount they wanted,and eventually tried to arrange to pay in instalements but while this was on going I sold my house and moved to a new address I sent them this with a letter asking to pay by instalments but never got a reply until last week I had a letter from land register stating solicitor wants to put a charge on my house they gained a ccj on my old address 5 years 3 months ago according to details sent through not sure what to do any advise would be appreciated.