Hello,
I don't know what statistics you want to send, but I would recommend you to create a custom plugin for that.
Via your custom plugin you will be able to do the database queries to retrieve the statistics you want and then send the email.
The HikaShop core functions would help you for the email part and you can also use the HikaShop cron system for your plugin, it will allow him to be notified in "background" and send the emails once a month.
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.