Ingresos brutos (English: total income) is a swingeing tax retention that you pretty much have to pay in advance of your income if you're self employed. For example, you make a monthly contribution and then it's tallied up at the end of the year against your actual income and then adjusted. At least that's the theory and the way I understand it.
Adri's lad had some virtual money he wanted to put into my Mercadopago (MP) account to buy something because the system is so simple and the only way he could do it was by MP.
If he transferred it to Adri's bank account she would have to pay 3.5% ingresos brutos which is retained immediately at her bank.
So he paid it to my MP and they took it from there instead.
The tax authorities have the power to dip into your account like this, so it's no wonder the black economy thrives so much. They steal it at source.