I remember reading, a few days ago in one of the advice booklets from the DWP - can't remember for the life of me which one now, due to brain fog. That you can ask for money from the DWP if you think they have made a mistake and caused you anguish or inconveinience.
I have had three letters from them now, asking for an overpayment of £200.00 for In work credit, which I have already paid.
Despite sending in a copy of my bankstatement, showing that the money has been paid, letters and telephone calls - I got another letter this morning threatening me with legal action if it's not paid within 7 days.
You need to write a letter to the customer services manager of the office sending you the letters saying you wish to make a formal complaint and that you consider that you should be awarded compensation for the emotional distress caused by the DWP's maladministration.
Send a copy to your MP's office and note on your letter to the DWP that you have done so.
Good luck,
Steve
Nothing on this board constitutes legal advice - always consult a professional about specific problems