If you are using a custom theme, it's likely that you will need to alter the vqmod/xml/openstock_customise.xml file for OpenStock to correctly work. If you are unable to do this yourself, we offer a custom theme patching service available on our store.
On the Journal Theme, our regular patching service is only valid when "Button Select List" is turned off.
This patching service is only valid for stores that haven't installed 3rd party option modules or changed any code that affects the options system in OpenCart. If you are unsure, please contact us and we'll provide a quote.