I posted about this a few weeks back.
My mum received a letter from the pensions credits people saying they wanted to review her beneits between 2005 and 2010. So i phoned them up and said to hold off beause my mother is ill. Told them that there had been no change in her income during that time. Was told they should have reviewed in 2009 but it was overlooked
.
Have been fully open with them in the past with regards to how much my mother receives from my late fathers occupational pension.
Have made a complaint, received a letter today saying that they are sorry that the review didn't take place but they have not taken into account the railway pension my mother will have received since my dad pased away when calculating her pensions credits. 
This to me, means she has been receiving too much money for 8 years 
and not only does this mean she is going to have a drastic fall in income but they are going to try and recoup the money that has been paid to her and reduce her benefits even more :(
WTAF??? We sent all the apporpriate paperwork off when my father died as this would have changed the amount of PCs she was entitled to anyway - so if they were unaware of the railway pension that is their mistake not my mother trying to with-hold information.
Am considering whether she is going to need legal advice? My mother is 75 years old, in poor health, has a medical condition that means she is "physically" as opposed to just mentally, unable to deal with stress and it can be extremely dangerous for her. She has just got over some horrible tests etc following a cancer scare and is still unwell from this.
How the hell do i tell her that her money is potentially going to be all but stopped? Surely they can't do this? Its their fuck up.
Of course is she is receiving too much then the amount she gets will have to be reduced i realise this, but with regards to back pay, we are talking 8 years - this could amount to thousands of pounds
This could kill my mother