moved to mailchimp, feed was exported then deleted. Now there are broken feedburner links everywhere

[Karen Aber Ploransky]

I recently installed Mailchimp for my blog newsletter, signup etc.  The feedburner feed was exported to mailchimp and then disabled.  I noted that the feedburner code was still in simple hooks in my WP site and after asking, I went in and deleted my feed as directed by a va!  now there are broken links everywhere.  Is that normally the case and do I need to do something about it. 

It was suggested that I reactivate the feed and then use the Better Search and Replace plug in to redo or reconnect or re-whatever it does to fix the problem I did reactivae the feed and was going to use the plug in which cautions to backup first.  The WP backup says I need to enable two options in the php _ the top two of which one is system and I can't remember the other right now) and I have no knowledge of code and have no idea how to enable them.

Any suggestions or help would be appreciated.

On a hamster wheel here.  Anybody??