I understand the logistics required for such a process. I'd have to create 3000 individual e-mail accounts, then set up 3000 individual Instagram accounts.
I will provide both the e-mail account's e-mail addresses and passwords, as well as the Instagram usernames and passwords so that you are able to manage both should you need to reset passwords, verify accounts, or build out more social media accounts with the e-mail addresses in the future (including Facebook, and Yelp).