Somebody else uses my account and stop my music by connecting with another device (not my device).

[OpTicNickson]

Hello

You can only stream music from one device at a time per account. 

This is because Spotify is a personal streaming service.

However, you can listen to an offline playlist on one device and stream music from one device.

If someone you don't know is accessing your account, you should contact Spotify customer support immediately because they have access to your details that you have entered upon regestering.

Here is a link to Spotify Customer Support:

https://support.spotify.com/us/contact-spotify-support/

Hope this helps

Feel free to private message me regarding all this.

Nickson