Starving a pensioner

My dad passed away in December and to date my mom has been sent from pillar to post with regards to the balance of my dad's RA, of which she is the beneficiary. At first they approved the claim saying she'll be paid out in approximately 6 weeks. To date she has not received the money. Their new found excuse that's mind boggling to me is that my dad owes them since they mistakenly paid him his income in December unaware he had passed (I don't know how since we called them and also went to their offices within days of his passing). So, where I question the logic being app**** at this company is in the fact that the balance of the RA is way greater than this so called debt. Why not deduct it from there and pay my mom the balance? It's shameful that a pensioner with limited resources has to make repeated trips to your offices and be told to write a letter of grievance because it's a HO issue. In the meantime my mom is incurring debt as my dad's income was the main source for running the household and day to day expenses. What do they think she's eating while she waits for this money? Anyone with two braincells can figure the reason for withholding the money is nonsensical, and the lawyers winding down my dad's estate have confirmed as much. No wonder the company is so terribly rated on hellopeter... This is ****gery