Hi,
Please note that HikaShop 3.5.2 does not exist.
If you want to have access to the original code ; you can make a copy of the content (in a local file) and delete the customization, so it will re-display you the original content.
You can also access to the file using FTP, in the folder "media/com_hikashop/mail".
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.