What is the ruling on the surplus money that the bank deposited in my account from the sale of additional shares that I did not request or pay for, and what should I do with this money after five years? Is it permissible for me to keep the profits from prohibited shares acquired in the past before I knew the ruling? And what should I do with the profits I earned from my shares?

It is not permissible to buy shares in usurious banks, because usurious banks are based on usury, and a severe warning has been issued against dealing with it.

If you bought these shares without knowing they were forbidden, then there is no sin upon you for that, and you are not required to dispose of the profits generated from them, due to the Almighty’s saying: (So whoever receives an admonition from his Lord and desists, he may have what has already passed), and because money that is forbidden to acquire - like the money of a usurer - is forbidden only to its acquirer, and is not forbidden to one who takes it through a permissible means, such as a gift.

You are required to dispose of these forbidden shares by revoking the contract with the bank. If revocation is not possible, then it is permissible to sell them to get rid of them.