I created a custom function to retrieve an account balance. It is declared as Public Function.

I now need to enter this function in a cell on another worksheet where the balance of the account must be displayed. So I enter 
=Get_Account_Balance(cAccNumber, dDate)
into the cell where I want the balance displayed. When I first enter the formula in the cell the balance is displayed correctly. When I do other transactions and then do a Application.Calculate the formula is not recalculated. Pressing F9 also doesn't recalculate the new balance.

What am I missing or doing wrong? Why is the formula not recalculated?