The Special Court of Brazil’s Superior Court of Justice has concluded the merits judgment of Theme 929, which addresses the circumstances in which consumers may receive twice the amount improperly paid under Article 42 of the Brazilian Consumer Protection Code.

The ruling removes the need to prove subjective bad faith, intent or negligence on the part of the supplier.

Instead, the analysis focuses on whether the improper charge was inconsistent with the principle of objective good faith.

The merits were decided on September 15, 2026. The official STJ database currently lists Theme 929 as decided on the merits, while publication of the full judgment remains pending.

How companies respond to complaints becomes increasingly relevant

One of the criteria announced following the judgment is particularly important for businesses.

Failure or refusal to address a consumer’s prior notice regarding an improper charge may constitute sufficient evidence to support a claim for a double refund.

This places greater emphasis on internal complaint-handling procedures.

An operational billing error may create greater legal exposure if the company continues charging the customer after being informed of a possible irregularity.

Suppliers may need to demonstrate appropriate conduct

The announced framework also places significant importance on evidence produced by the supplier.

Companies may be required to demonstrate that they did not act contrary to objective good faith and that their conduct was neither disloyal nor careless.

As a result, customer-service records, system logs, billing rules, internal reviews and communications with consumers may become important evidence in litigation.

Not every billing error automatically results in a double refund

The judgment also recognizes the concept of a justifiable mistake.

According to the criteria announced following the decision, this may include situations involving genuine disagreement in existing case law or charges based on contractual provisions that were only subsequently declared invalid.

The analysis therefore remains dependent on the circumstances of each case.

Automated billing requires stronger governance

The decision is particularly relevant for organizations that process recurring or high-volume payments.

Banks, financial institutions, telecommunications companies, subscription businesses, digital platforms and utility providers increasingly rely on automated billing systems.

Automation improves efficiency, but a system error may also reproduce an improper charge across a large number of customers.

Billing governance should therefore include mechanisms capable of identifying, interrupting and correcting errors quickly.

Integration among customer service, finance, technology, legal and compliance teams can also help prevent a known billing issue from continuing after it has been reported.

Theme 929 therefore reinforces a broader risk-management principle: companies need not only accurate billing systems, but also documented and effective procedures for responding when potential errors are identified.