The Tezbox service has been shut down. Tezbox provided a web-based Tezos wallet and a desktop Tezos wallet for MacOS and Windows. If you are still using one of these wallets then please change to a new wallet.
You can easily set up different wallet software by using your seed phrase. This is the phrase that you generated when initially setting up your Tezos wallet. A list of Tezos wallets can be found here: Tezos wallet.
If you have any questions, you may ask us here: support(at)tezbox.com. Please do not share any seed phrases, neither with us nor with anybody else.