I suggest contacting the support team over @Artists for Spotify. Also the duplicitious artist names are due to the different distrubution companies you might have used. If you go to song details, you should see the listed companies underneath. I hope this helps!
I had the same problem. The only thing to do is to claim one of the artist profiles via Spotify For Artists. You can then request to merge those two artist pages there by contacting Spotify staff. No matter who the distribution companies are.
In my case it ended with me e-mailing the Spotify staff the complete list of all our recordings that should be on our artist page (with the Spotify urls), also including collaborations (... from the "apears on" section).