Icons (checkout, delete etc.) are visualized as code (f007 etc.)

-- url of the page with the problem -- : www.notteconvenienza.it/ecommerce1/
-- HikaShop version -- : 3.1.1
-- Joomla version -- : Joomla! 3.4.3 Stable [ Ember ] 2-July-2015 16:00 GMT
-- PHP version -- : 5.5.38
-- Browser(s) name and version -- : chrome 61.0.3163.100 (Build ufficiale) (a 64 bit)

Hi all,
when I go to checkout and get back after payment or payment aborts, the icons on the page are showed with their code (i.e. f007)
Thanks for your help.
Vivaldo