How to sue the dwp

[chocolate lover]

Am i doing all i can? My fatherinlaw suddenly passed away and we applied for funeral payment. My motherinlaw got a letter confirming 1572 payment. Three months later my mother in law got nasty letters and threats from funeral parlour the dwp said she wasnt entitled and only paid about £300. All this time my motherinlaw was suffering with bowel cancer and although we advised them to leave her alone and contact us,both dwp and funeral parlour constantly badgered her. They called her to court 3 times-they didnt send paperwork and when they did it was wrong.They never turned up.My motherinlaw passed away before finding out the judge ruled in our favour and noted their deplorable behaviour. I have gone through my mp.The case has gone to ice and then to be passed to ombudsman. Is there anything else i should be doing? Can i personally sue dwp /funeral parlour?