Schedule/Appointment Integration

-- HikaShop version -- : 2.4.0
-- Joomla version -- : 3.3.6
-- PHP version -- : 5.4.32

I am looking for an appointment or scheduling extension that will integrate with Hikashop. I want clients to be able to schedule a service appointment from my website and then have the option to pay for it upfront or come back to the website and pay their invoice later. Any suggestions?

Thanks!

Thank you! Just what I need.