If all calls are being imported again, then the amounts for
all the calls imported will be subtracted from the monthly
budget amount.
Therefore if data of a couple months is imported, all budgets
will be exceeded. If barring is used, then you need to reset
all budgets to enable the phones again.
[SETUP -> PROPERTIES -> FILTERS & DEFAULTS]. Under
"Enable Budget", click on "RESET ALL", to reset all the users.
Please note that all budgets are now reset to the full amount
available for that user.