Garanti BBVA Changed My Loan Installments Without Notice and Denied Interest Refund

Garanti Bank changed the date of the loan installments without my knowledge. And the loan that should have been 5 installments is shown as 6 installments. There are 2 installment payments in March. When I went to the Kadıköy branch, they said this is a business house and you are expected to pay the full interest. Despite making all payments on time, I was never informed about the change in the installment schedule. The bank’s lack of transparency and irregular actions have caused financial inconvenience. Garanti Bank is acting irregularly!!! And although I closed the loan early, it does not give the interest refund! I request an urgent solution to this complaint!