As known from legal tender Physical Cash, the refund capabilities of anonymous eCash are limited. A user of our fairCASH system must proof his ownership in case of any eCoin loss for a possible compensation. He needs to know his eCoin serial numbers; this can be achieved by maintaining a (with respect to the loss previously done) backup of the transfer logs (but not the eCoins) or by asking the previous eCoin hop source to hand out this information.
This needs to be reported to the eMint, so they can check if the requested eCoins are really lost (meaning that they are still not deposited) and refund them AFTER reaching their transferability expiration validity cycle in the off-line loop, but BEFORE the clearing period has expired.
Payments are irrevocably, cancellation of successful transfers already done is fundamentally not possible. Refundability should not be mixed up with recoverability, which is not a feature within our fairCASH system as such a property generally conflicts with many others, e.g. untraceability.
Our fairCASH system provides limited refundability: lesser than accounted systems, but better than Physical Cash. In addition to that, eCoins are protected by the well known mechanism of PIN (and PUC) to "open" the eWallet, so that unauthorized persons cannot use the value as it is the case with Physical Cash.