Formula reverting back to original after refresh

Hi Experts,

We have a report where I need to make changes to the displayed text.

It goes something like

A     B                    C                         D

1     Account            Department         Heading

2   ExecutiveExP    Dep1                    =if(b2="executiveexp" & c2="Dep1", "HR", "Total")

3   ExecutiveEXP    Dep2                    =if(b2="executiveexp" & c2="Dep2", "Finance", "Total")

4   GeneralEXP     Dep3                      =if(b2="executiveexp" & c2="Dep3", "admin", "Total")

5   GeneralEXP     Dep4                      =if(b2="executiveexp" & c2="Dep4", "marketing", "Total")

The report worked fine all these days, but recently the user changed the account member "executiveexp" to "execexp"

So I changed the if formula to

=if(b2="execexp" & c2="Dep1", "HR", "Total")

but after refresh it it reverting back to the old formula.

Is there any way to sort this?

Regards,

David