Any advice ?

[des8]

Re: Any advice ?

You then have a bigger problem
If you notified HMRC and they did not amend your tax credits you have an argument to be used against them.
If you did not notify them, they are correctly recouping the overpayment.
This means you will now have to convince DWP that you were not entitled to tax credits for the period for which you received JSA, and that their advisers should have known this and taken it properly into account. You already know how difficult this is.

You will need to work out your figures and dates exactly,and IMO try one more time with DWP.
If they don't agree or don't respond you could then enlist the help of your MP.
If that fails your last resort will be a county court claim.

[Takethis]

Re: Any advice ?

Sorry forgive me what do you mean by IMO ?. So do you suggest I write another letter to DWP (keep a record and get proof of postage) and see what happens/ what response I receive ? Is there anything you could suggest I include in the letter.....?? I think my only way of trying to get this sorted is through DWP and not HMRC because my husband has just taken the advice of the JSA advise (SILLY MISTAKE). Would it be worth me taking legal advice or do you think I would be wasting my time ??? Thanks again.

[des8]

Re: Any advice ?

IMO = in my opinion (not that it is necessarily worth much!)

If your husband did not inform HMRC of the change in circumstances, I do not envisage them helping.

You need to get your figures and timeline accurate.
Find out from what dates the amount of tax credits should have changed. This is what HMRC are reclaiming and what you need to claim from DWP as an underpayment.
Explain clearly that when claiming JSA you husband thought he was entitled to the amount of tax credits he declared, but he was wrong and was not corrected in his misapprehension by the Job Centre staff.
As HMRC are now reclaiming the overpaid tax credits it means he was underpaid JSA by the same amount, and so that is what is being claimed.

Obviously you can take legal advice (try and find a solicitor who specialises and will offer a free first time consultation) or talk to CAB