Sorry to hear you're having trouble with this. We'll be glad to lend a hand.
Do you notice the speaker being duplicated across all of the devices you use that are on the same network?
Does logging out and back in a few times make a difference? Also, when you reinstalled, did you follow these exact steps for a reinstall? Make sure you clear your cache before installing the app again.
I have deleted everything and unstalled the spotify. The problem persist. I have other wifi speakers in the same network that works well without duplication. Only this BOSE SOUNDTOUCH 30 is the problematic. I sent the speaker to BOSE and they told me there is nothing wrong with the speaker and charged me for the service. They say it is spotify related issue. Please tell me how to solve this.