You can trade Ethereum for Bitcoin using
https://shapeshift.io/#/coins . No account needed. Go to Youtube to watch videos on how to use them, and then apparently (I've never used them) sell the Bitcoin using
https://www.satoshitango.com/faq. Satochitango charge a 2 % fee per transaction, ouch. Their website says they can pay you with pesos. I would imagine you would have to have a DNI card to receive cash. I'm not endorsing them, just saying they exist. Please let me know if you do use them and are successful. My crypto guy's charts today shows ETH going up to around $2400 in March and Bitcoin to 28 K, Of course there may be some hefty retracements along the way.
How can I sell bitcoins with SatoshiTango?
Selling bitcoins with SatoshiTango is safe and easy. Simply select the amount to exchange and send the bitcoins to the corresponding address. You can receive Pesos in your bank account through a local transfer or in cash if you live in Argentina, you can receive US Dollars in your bank account through an international wire transfer or you can receive Euros in your bank account through a SEPA transfer. You can only receive funds into your personal bank account. Due to ongoing regulations We are not allowed to send funds to an account located in the United States.
To learn more about cryptos , attend the Tuesday coffee chats. Those people know what's what.