Does wrongful charge restitution always double the amount?
No. Doubling only applies in a consumer relationship, under CDC Article 42, sole paragraph, and only automatically for charges made after March 30, 2021, under STJ's EAREsp 676.608/RS; charges before that date, ordinary civil relationships and wrongly paid taxes follow other rules, often resulting in a simple refund.
Why does March 30, 2021 matter for consumer wrongful charge restitution?
Because that is the publication date of EAREsp 676.608/RS, decided by the STJ's Special Court, which gave prospective effect to a shift in doubling doctrine: charges made after that date double regardless of bad faith, while charges made before it only double if the supplier's bad faith is proven.
Can an overpaid tax be refunded twice over?
No. Restitution of federal taxes wrongly paid is always a simple refund, under CTN Article 165 and Lei 9.250/1995, Article 39, §4, updated by the SELIC rate as the single index for both monetary correction and interest; the CDC Article 42 doubling does not apply to tax relationships.
From when does monetary correction count in wrongful charge restitution?
It counts from the date of disbursement, meaning the wrongful payment itself, under STJ Súmula 43, not from when the lawsuit was filed nor from the ruling that recognizes the wrongful charge; when doubling applies, it applies to the value that is already corrected and bearing interest, not to the charge's historical value.