http://instagress.com/

Had a great experience with Instagress. I used it to mass-comment and drive traffic to my main account. I had signed up with five accounts, all commenting (tagging my main acc). Main acc raked in around 250 followers a day. But then I switched to a bot because it does come with quite a price tag in the long run. The password reset is because Instagram detected a log-in from a new location. Once you reset, you'll be able to sign in again. Only two of my accounts needed to be reset. I also had my settings on 'Fast'. My experience lasted a few weeks so I cannot say whether 'fast' would be safe for long term (although, few weeks is quite a while in Instagram time).
My main Instagram is a niche acc, and all five accounts were commenting on tags in that field. Can't be sure it would be as successful for random accounts with no certain demographic. Hope this helps.

I ve been using a lot a different instagram bot.
Instagress is reliable and efficient! Not too pricy.
Also, if you wish to have several accounts for massive like, comment and follow op, you will need proxies to acces from your place, otherwise you ll get banned.
Once I got that, never been banned again