First check your usage pattern or online details.
If you notice charges for local and national calls, you exceeded your call time limit of 59 minutes per call. Hang up once you've reached 59 minutes and you can call again for free.
If you notice charges for your 3 Vodafone mobile nominated numbers, then you may have updated your numbers in the middle of the month. The call allowance for these numbers doesn't apply until the start of your billing period.
If you have exceeded your monthly call allowance (e.g. 100 minutes to Irish mobiles) then you will be charged the out of bundle rate. You can keep track of your call usage from your My Vodafone At Home online account.