Create a Wordpress Template Child Theme

I have a website created on a customized wordpress theme. I need a Child Theme created so that my custom coding won't break when Wordpress updates to the latest version AND when the theme updates to the latest version. It looks like I have a version of a child theme in my account that is active, however, the entire site keeps breaking after the automatic updates for the theme and/or Wordpress updates. Here is the Project Description: 1. You MUST be able to create a new Child Theme from scratch or fix my Child Theme so that it does NOT break the custom coding of the theme during theme updates and Wordpress updates. 2. After completing the Child Theme, you must update everything to the latest versions (both theme and Wordpress installation). 3. The site MUST stay up and running while you are working on this project. It cannot come offline! 4. You must be able to complete the project within 7 days of earning the project. This should be fairly simple for anyone who knows what they are doing. I'm also looking for someone for future projects to rebuild existing websites that I have, so if we work well together and I like your work, then I will definitely consider you for the bigger projects later this year. Please respond with "preserve" in the subject line so that I know you read this entire description before bidding the project. I will only consider you if you follow this instruction. In addition, please confirm that you can successfully complete all four of the tasks that I listed above under the "project description."