VAT refunds: Is the government unjustly enriched?

One of the well-known and time-honored principles in the Law on Obligations and Contracts is solutio indebiti. The rule is that no person shall unjustly enrich himself at the expense of another. Accordingly, if something is received when there is no right to demand it, and it was unduly delivered by mistake, the obligation to return it arises. In such a situation, a creditor-debtor relationship is created under a quasi-contract. The payor becomes the creditor with the right to demand the return of payment made by mistake while the payee, who has no right to receive the payment, is obligated to return it.