I tried to update the company logo but when I save it returns back to default, how can I do this without editing the default template?
Can you clarify what you mean when you say it "returns back to default"?
What I mean is that instead of returning a success or failure message, it redirects to the theme link.
Can you check what error messages you see in your browser console while on that page? (/admin/extension/settings/system)
It sounds like there's a misconfiguration with your server which is causing the API wrapper to not be loaded correctly inside the admin panel