Calculate effective rate of the loan - additional fees

Question

I am having following parameters:

loan_value = 20000
Annual rate = 2.9%
other fees = 500
periods of repayment = 24 (2 years, each month)
additional fees per month = 2 

now, given the formula:

EIR = loan_value * (1+Annual rate/24) power (periods of repayment) I get EIR of 2.94%, where did my bank get 5.78% ??? I would really appreciate the explanation.