Your bank IBAN is linked to your personal bank account, while your Ziina IBAN is provided for your Ziina account.
The IBAN shown in your Ziina app is your Ziina IBAN. You can use it to receive bank transfers directly into your balance. The two IBANs are separate, so your Ziina IBAN doesn't replace or change the IBAN of your personal bank account.
When someone wants to send you money by bank transfer, make sure they use the IBAN shown in your app.