The best alternatives to CallBox are Dakiya, HTC Exodus, and ADAMANT Messenger. If these 3 options don't work for you, we've listed a few more alternatives below.
Using dakiya you can send messages to anyone with a wallet address, without having to create an account or relying on email servers. The messages are encrypted using the public keys of the recipient. It costs gas to send a message - so important messages only!
Send anonymous SMS messages using the Binance Smart Chain. All SMS messages are paid anonymously with BNB tokens. All SMS messages are encrypted end to end.
Write a custom text message that will live forever on the Bitcoin or Ethereum blockchain, without any technical steps. You pay the transaction fees with your debit or credit card.
UNCO is an anonymous messaging and communication app that empowers people to shape the world by sharing their ideas, secrets, and what others dare to say. With UNCO, our differences are a source of inspiration and development.