We recommend that you regularly generate backups of your CoinTracking account via Account/Trades Backup. In addition a backup before you do major changes/adjustments within your accounts is sensible. In case you did not create backups on your own and delete your data accidentally, we have no possibility to restore it.
You can restore your data if needed within your account. If you are using multiple linked accounts you can restore the backup data from Account1 into Account2 as well.