How Do I Get My Un-allocated Dangote Flour Shares Money From Oceanic Registrars

i bought dangote flour mills public offer from oceanic registrars through diamond bank and since the shares was said to be over subscribed, un allocated funds were returned to investors but up till now i have not been able to get my un allocated money back. i went to diamond bank to check for the money, i was told there was no provision for it from the oceanic registrars, please i need help on how to get my money back from these banks. thanks