I would like to know whether dealing with Cryptocurrencies is halal. I used to believe that it was halal, and therefore I have bought and invested into a particular cryptocurrency called Vechain (https://www.vechain.org/). Since I already own Vechain, I need to know whether it is halal or not, and if it is not halal, then what action do I need to take from there?

Till this day they are not allowed. You have bought, you manage them. Inshallah soon it will be allowed.