A chargeback transaction happens when an offer that you completed gets invalidated after you have been credited for it. Chargeback transactions are always negative because they "reverse" a positive offer transaction. Chargebacks are final, we can't undo them. You will need to contact the corresponding offerwall provider if you believe that a chargeback is unjustified. Please note that too many chargebacks can lead to a frozen account balance.
Let's say you complete an offer that is worth 5,500 points. After you completed the offer, the offerwall provider sends us a notification about the completion. At this point, we assume that we will get paid for the offer, so we credit your account with 5,500 points.
But a few hours or days later, the offerwall provider finds out that something about the offer that you completed was not valid. It might be that you used a VPN, multiple accounts, or that you used fake information to complete the offer. So the provider sends us another notification that tells us that the offer has been invalidated and we won't get paid for it. At this point, we will create a chargeback transaction that removes the 5,500 points from your account. That's because if we don't get paid, we can't pay you either.