Instagram post scheduler bot to manage multiple accounts in advance

Hey, is there any bot with that you can manage ~ 10-50 accounts to prepare content and schedule the posts ?

I want to plan with every account 3 posts a day ahead for one week for specific times to grow all of them together.

Is there any service for this?

> Hootsuite

too expensive ($500 a month) to manage that amount of accounts and I only need one feature to post.

> Jarvee

doesn't work with posts as instagram detects that and the hashtags are not working if you post with jarvee.

Hashtag not working on jarvee? What?

You can try GMT2