Hi,
I'm sorry but HikaShop 5.6.0 does not exists.
And Joomla 3.6 neither.
If you remove the "option=com_hikashop" in the URL which allow to confirm the user ; the link won't work anymore.
It's not like we wanted to make "hikashop" visible in that URL but ; it is like some kind of obligation if we want to let the HikaShop checkout controller be called by Joomla, process the data and confirm the user registration.
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.