Yes, I realize that I didn't provide link. Here it is:
www.elktis.com/en/shop
Also, there is screenshot of checkout settings, as you requested.
Meanwhile, I was exploring problem a bit deeper and I discover that issue is somehow connected with template. If I switch to joomla "native" template Protostar, I get everything works.
From your experience, where is the problem exactly? Template used in frontend works just fine in all other aspects.
Also, I can give you backend admin credentials, but let me know how to do it. If I post them here, they will be public which is actually bad idea, right...?
Kind regards,
Dejan.