How can cashback be added to a transaction?
Starting from REST v2 and WS v1, cashback can be added to a transaction via Connect. If the card terminal does not support cashback or the card does not allow it, the transaction may continue without the cashback amount. The amountCashback field in the transaction should always be checked to find out the actual amount of cashback processed.
Previous API versions do not support cashback from the EPoS, but it can still be added manually on the card machine as is described here
What is the signature verification process?
When a signature is marked as not accepted via our API, Ingenico PDQs will perform a reversal to void the transaction. This is an industry standard approach for semi-integrated solutions.
Why does the cashback amount differ to the actual cashback amount processed?
Ingenico terminals in Pay-At-Table scenarios only offer limited support for notifying Connect - and therefore the EPoS - of the cashback values added to transactions. This is because cashback is a rarely requested feature when a bill is settled at a table, due to its inconveniece. When this value is available to Connect it will be set in the response, otherwise the response value will be set to its default.