Decouple t-mobile from my account

Hi

Because of some unknown reason my account became free and did not connect with my T mobile premium.

I had to log in and connect with T Mobile again. However by mistake I used another deezer account of mine which was free and I was not using (its the account I am conversing with now).

So now I have accidentally connected this account with my T mobile premium. I would like to undo that, so I can get the premium back on my old account. The one where I have my playlists and everything...

A bit confusing but I hope that the essence of my question is clear ( the decoupling of a t mobile account so I can couple it with another).