Hi,
The cart is stored in the browser session.
If another browser is used for the activation link it's logical that the cart will be empty.
If the domain name is different (like
www.mywebsite.com
and mywebsite.com) and Joomla is not configured to create a shared cookie, it could explain the problem too.
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.