{Include File="meta.tpl"} Deleted From Index.tpl Automatically

This morning our website stopped working responsively. later i detected that meta.tpl was not included in any of the frontpage.

Then i checked that index.tpl file in responsive/template folder was the latest modified file in design folder for today early morning 07:59 AM. and a the line including the meta.tpl file was missing.

How is it possible that this 1 particular file was edited on its own by the system?

what are the possible options other than someone did it by having the cpanel password.

File: design/themes/responsive/templates/index.tpl

Line Removed: {include file="meta.tpl"}

Line Number: 47

CS-Cart Ultimate 4.3.7


Hacked by a competitor who wanted to break your site in a subtle way just before Christmas????

Or maybe you inadvertently edited the file.

Please check user access log in the admin panel and check if there are any unknown administrator logins