fixed term rate

On the 17th of December 2021 my fixed interest rate expired and for the month of December 2021 my bond repayment was prorated which I completely understood as it made sense. However January 2022 is a full month and I am still debited the same amount as last month which does not make sense to me. Contract clearly states that " Fixed rate - will only apply for the fixed rate term as set out below, whereafter the Variable Rate will apply." and the prime lending rate at the time was 10.25%.

Can FNB please review my January bond repayment as I believe it is not correct.