Welcome to the Q&A Forum

Our company recently rebranded and launched a new website. The website was developed by an overseas team and they created the test site on their subdomain. The only problem is that Google crawled and indexed their site and ours. I noticed Google indexed their sub domain ahead of our domain and based on Search Console it has deemed our content as the duplicate of theirs and the Google selected theirs as the canonical.
The website in question is https://www.spaziointerni.us
What would be the best course of action to get our content ranked and selected instead of being marked as the duplicate?
Not sure if I have to modify the content to make it more unique or have them submit a removal in their search console.
Our indexed pages continue to go down due to this issue.
Any help is greatly appreciated.