They are trying to rattle your cage...
Best thing is to refuse to deal with them on the telephone and insist on all communication via letter. That way they can't accuse you of saying things you haven't or misconstruing what you say.
Have a look at the Civil Procedure Rules. Also, there is s40(a) of the Administration of Justice Act 1970 which is useful. It states that a person commits an offence if he/she:
“harasses the other with demands for payment which, in respect of their frequency, or the manner or occasion of making any such demand…….are calculated to subject him or members of his family or household to alarm, distress or humiliation”
Have a look at the National Debt Helpline site which mentions these rules/law and has template letters you can also download. The link is
National Debtline England & Wales | Debt Advice
Look at the letters and cut and paste as appropriate. Remember to keep copies of all letters you have sent so if necessary you can show the court how unreasonable D & G are being.