Hi,
With HikaShop Business you have a plugin called "group after purchase".
But that plugin is not a Membership / Subcription feature, it will just put the user into the group.
If you really want a subscription system, HikaShop have currently two integrations : Akeeba Subscription & Emerald Subscription.
See "Integration" section :
www.hikashop.com/support/documentation.html
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.