There are different types of orders implemented at Coinvest. Some of them have a delayed execution (limit order), and some are executed instantly (market order). Once conditions are met, orders are automatically executed.
In this case, the transaction is irreversible, but you can place another trade to attempt and cancel out the trade, minus any applicable fees.
Remember that you are your own bank when dealing with cryptocurrencies. Be extremely careful when making transactions.
Please contact firstname.lastname@example.org if you have any questions, concerns, or issues.