Sometimes it happens that an upgrade fails and you forgot to make backups. It's not the worst thing ever that can happen. It is usually fixed easily.
When the upgrade halts, LiteCart will have successfully applied all patches prior to the version patch halting. So they will not be applied again. However when resuming the update it will try to apply all the commands again for the version that halted. We need to edit that failed patch and remove all commands that were successfully applied.
The upgrade output in the browser window should provide some feedback of what command that may have halted. Or there could be some information in logs/errors.log.
When you are reqady to resume the upgrade, simply refresh the halted page allowing the browser to issue the form request again.
Hopefully you are back on track again. Come talk to use in the forums if you need support.