Brand was approved but it’s already in use?

I got a trademark to my brand name let’s say “magic cush” the trademark is pending and Amazon approves my brand registry. I contact them to try and change the brand on my already listed product with the brand name ON THE LABEL. But Amazon says “We cannot proceed with your request The proposed name Magic Cush is already taken and registered. Please try a different brand name” I searched it up and there is one product using that brand name and now I’m considering filing for infringement.

I’ve done my research and there is only 1 trademark with almost the same name as me but the words are together instead of separated by a space different class ofc. If thats the sane guy that’s on amazon then why did I get approved for brand registry for that brand name?

Should I file for infringement or not…?