Checkout does not appear

-- HikaShop version -- : 2.6.2
-- Joomla version -- : 3.5.1
-- PHP version -- : 5.5.26
-- Browser(s) name and version -- : crome etc..

Hello
I upgraded to the latest version all but then never shows me more details to proceed with the order in addition even if I click on the filter causes me a cart with a variant that is not the default without even having chosen, I send data access to try, if you try to make an order you see right away what it does.
Help me tomorrow I have to go online with an event that I photographed Sunday as agreed with dell'eveto organizers.
I had already sent the access data for administration if you've still servant send them away
Thank you

I'm sorry I was hoping you could settle before but I had to close the site to restore an old version, when it becomes fully functional to provide for a copy of the site test to reproduce the error again, I will keep you updated
regards