Hey there, Google is not able to access content under hashbang URLs. ( /#!)
Or to name it correctly: Google says they do indexing of hasgbang URLs but… obviously they have problems with these URLs. Otherwise people would not complain so much about that issue.
If you want to benefit from SEO at your own website, I´d recommend to use the shop´s navigation points and add it to the top navigation bar of your website. (instead of having the language switcher)
This way, Google is able to understand the content of your website only by reading the first 20%. This is called “above the fold”
As all shops have the same content structure to Google, the impact or advantage of indexing a single shop is not that big. It’s more useful to create your own website content around it.
Your webpage is already a good start