Bad service

I am very disappointed with Post Bank. My husband passed away in 2018 and he had a savings account at Post Bank, which our dividends from our Yebo Yethu shares are being paid into. Post bank has since refused to release the money in the account to me, saying Yebo Yethu should write them a letter stating they should release the money. Vodacom Yebo Yethu says they can't write a letter as they have already released the money and the matter should be between Post Bank and I. Please assist, what should I do in this regard.