My Husband Money Missing

On the 18 September 2024 I was using my husband's card on the ATM, I mistakenly transfer R25 000 to his credit card on the ATM. He is deceased now and I have all the documents which I sent to the FNB Deceased, but they are telling me that there is no transaction on the credit card. I'm not happy because It's has been 4 months since I'm busy querying this. Now I'm in need of the funds, urgently so, my lights will be switched off. I'm not happy with FNB because they can see this transaction on my husband's statement but cannot follow where the funds went to. How can I trust the bank now?