It sounds like a scam
I was in Angry from Harringay mode when I first posted. I neglected to say that DWP is department for work and pensions.
The letter shows my national insurance number.
I did think scam at first.
But, it is quite a scam if it is one.
Almost certainly a scam. Similar ones from HMRC, DVLA etc. Do not pay. If genuine you can appeal. Do not give them any personsl info. If it is addressed to Dear email address rather than your name its definitely fake.
Sounds like you may have already been scammed on a premium-rate number, what number did they get you to ring?, and did you google it?.
Scam communicationAs with any scam emails that make it through the work firewall, I forward on to IT so they are aware. In this situation lease forward on to the official DWP so they are aware. Link is for the official DWP.
Check a letter, phone call or text is genuine
Letters and forms
Any letters and forms will have the Jobcentre Plus or Department for Work and Pensions (DWP) logo.
A current scam involving the DWP and an unexpected debt letter is described in the link below. In that case it was done by online impersonation.
If this is what's happened in your case, it can't be binned like nearly all scam communications can, it sadly seems.
Hmmm that doesn't sound good. The rest of the letter looks genuine and phone number given to call them is same as on gov.uk.
The letter mentions getting help from likes of citizens advice bureau so in absence of being able to speak to dwp that seems a good next step.
There's a National Benefit Fraud Hotline, 0800 854 4400 which may be useful. A bit more info here.
thanks for everyone's replies on this