Hi,
For bug reports ; please be sure to use the latest version of HikaShop (currently, 2.6.1).
When you register and come back in your website, if you're using a different browser or the URL is not the same ; it is possible that you'll have a different session.. and could have a different 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.