Now it seems it's even a big issue finding a remote that will work with it. I bought a universal remote and it works with all my devices but my new(yet so old) RSQ E500N is not to be found. I've looked through a lot of remote manuals and there are brand names I've never heard of before but my RSQ is not to be found.

Is there anyone out there with the knowledge of what I could do?

Your best bet is to buy the original remote for the Karaoke player. They are only $14
[Link: spencertified.shop]

There's also a $35 remote at another site, but since I live in Sweden I probably would be better off buying another device...import taxes and shipping can add up..

On another note if I could get the code, the Italian company that makes the universal remote that I bought might update their list of codes to include the RSQ E500N. It's the type that you program via your pc with a usb cable. (The remote actually worked with my JVC Xl-mv3 right out of the box.. but then again.. JVC is one of the more established brands.)

Keeping my fingers x:ed for a solution :D

If you haven't already tried, go thru the codes from other manufacture. Start with Pioneer codes, they were used by several Karaoke branded players.
Also try Awia, Akai, Audiovox, etc.. I would be surprised if at least 1 of the code sets in your universal remote didn't work at least some of the functions of that unit. May take some time to go thru all the codes.