The fact that you say 6 texts, suggests you can see the totals on the spread the word section here Http://giffgaff.com/profile/usage-statement
Is that the case?
Those ammounts are not necessarily what you've been charged for
They're ammounts you would save if the numbers were on giffgaff AND you were using payandgo rates
If you were using a goodybag, the information isn't relevant
To check any airtime charges look on the balance usage
(where it says data, minutes, texts, international, roaming)
Could you post the charge against each item