annt73
As the call you mention was made on 18/3 it could be that at the time you made it your bag did not have unlimited minutes but was still running on the old allowances.
The changes were only applied to bags bought on or after Feb 26 they were not applied retrospectively to bags that were already live.
So if the bag you had on the date the call was made had been bought prior to the increase date then you may well have, in the mistaken belief that you then had unlimited minutes, used up all your allowances and thus been charged for calls.
If this is not the explanation then you would need to raise the issue with an agent.
https://support2.giffgaff.com/app/ask/Top-up-balances-and-goodybags/goodybag-allowances-or-credit-balance-incorrect/
