PPI Claim Freemans and Graaton Holdings

I made a PPI claim against my deceased mother's account with Freemans catalogue and they eventually replied asking me to get a letter of Confirmation form the court before they would deal with me. The court clerk was quite clear that they would need to supply an amount to be entered on the letter so I went back to Freemans and explained all this to them.

They claimed they could not discuss anything with me despite me having dealt with them and I insisted that there was little point protecting information pertaining to a deceased persons account and that in any event, all I was asking for at this stage was for an amount (if any) to be recorded in the letter of confirmation. They said they would get back to me and a week later they hadn't so I called them and they now say there was an amount but have used it to pay against an outstanding balance.

I think there WAS an outstanding balance but my mum died three years ago and I genuinely can't remember. I suspect probably they CAN take any money owed from a PPI claim and pay it against an outstanding balance from an account they closed three years ago but my question is... can they?