I created an account long time ago which comes with x amount of $ for free. Somehow it got below the threshold, and Nexmo sends me an email every single day abo

I created an account long time ago which comes with x amount of $ for free. Somehow it got below the threshold, and Nexmo sends me an email every single day about my low account balance and tells me to add money. Since unsubscribing required me to login, now all the mail goes to spam folder. This is last 7 days: http://i.imgur.com/QhyMgCX.png http://i.imgur.com/QhyMgCX.png