Missed the Theta Mainnet token swap / Need to swap old ERC20 Theta Tokens
All ERC20 Theta tokens were swapped to the Theta blockchain when it launched in March 2019. Your mainnet tokens were created at the equivalent address to the one that held them on Ethereum. Sending the ERC20 Theta tokens after that date has no effect on Theta blockchain. To access your new tokens on Theta blockchain, import that ETH address into the Theta web wallet using the ETH address private key. This must be done on the Theta web wallet on desktop, not the mobile Theta wallet. If your Theta tokens were stored on a Ledger/Trezor address, you can access your swapped mainnet tokens at the same address using your Ledger/Trezor with the Theta web wallet.