Hi,
Your website is using HTTPS.
but you have some links with HTTP in your website, specially the sub menus.
When you open a HTTP page, the session is lost (I guess due to your session configuration) and the user is redirected to the HTTPS version of the page.
The result is that, your previous session is lost and the server create you a new session.. with an empty cart.
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.