Here's a YouTube video on how to install code to the website.
It may be helpful to share this with the client if they're having issues installing it, or review and walk them thru the process.
Please ask them to attempt again and follow the below process precisely as outlined.
This code needs to be pasted immediately after the opening <body> tag: 
Step1
Paste this code as high in the <head> of the page as possible:
See below; they will need to insert this below that <head> tag.
Step 2
This code needs to be pasted immediately after the opening <body> tag:
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