Payback starts process around the 5th of each month, see payback full guide:
If then you think this is incorrect after the 5th, contact agents:
Hi thanks for visiting the community.
updates are 5th ov every month
payback is earnd bye helping other giffgaffers,
payback is payed out 2 times a year december + june you can only miss 1 payback pay out so you can add more points wich you can use as credit , send to paypal , or give to charety its a thank you from giffgaff for helping but if you dont choose 2nd time you will loose them https://giffgaff.com/profile/choose-payback-method.
Please don't forget to come back after your problem has been resolved and select a best answer.
Also consider a kudos [+★] for any member who helped.