IFTTT Instagram to Twitter applet not working

It will be a ten minute project but Flickr still supports what you want so if you register Flickr, or several other IFTTT file-hosting services, you can still post to your class instagram. I hope I understand well enough and that this helps, but here is what I would try:

Your Primary IFTTT Account:
If
{New Instagram Photo}
Then
{Save Photo to [SomeServiceFolderLikeFlickrFolderX]}

Your New Classroom IFTTT Account:
If
{NewFilOorImageLikeOnFlickrOrFTPRSS}
Then
{Post to ClassroomFacebookWall}

So essentially you need to set up another IFTTT account, link it to the classroom IFTTT, then set triggers in your personal account that transpose the image to your new IFTTT which will be linked to the correct page, whereat you can post.

IFTTT indeed prevents recipes from posting the @ sign. I believe this is a condition set by twitter to prevent IFTTT from spamming users.

The way around this is in fact using two separate IFTTT recipes:

1. Twitter to Google Sheets: use this recipe as Trigger to collect all the info you need like username, text etc... and assemble this info to compose the exact wording of the tweets you wish to send in a dedicated cell.
2. Google Sheets to Twitter: use this recipe as Action, to post the content of the dedicated cell to Twitter.

Posting from Google Sheets should resolve the problem.