You've still not said whether you're using an email client (such as Outlook Express, etc) or a web-based email service.
In Outlook Express (and probably in most other email clients) goto Tools > Message Rules > Mail. Click on the unwanted rule and then on 'Remove'.
If though (as I suspect) you're using a web-based system, I can't give you precise instructions. There are thousands of web-based email services and every one is different. You need to look for a link referring to 'Rules', 'Filtering', 'Spam Filtering' or something similar. (Sometimes you need to go to a 'Spam' or 'Junk' folder first, in order to find the link). Then you need to look for information about how to change, or remove filters. Some systems give you lots of options. Some only allow you to disable spam filtering completely.
Also (with a web-based system) go into the 'Spam', 'Junk', 'Trash', 'Bulk' or 'Deleted' folders to see if there's a box to tick alongside mail items, marked 'This is not spam', or similar.
I'm sorry that everything here has been a bit vague but the way that I receive my email is almost certainly different to the way that you do, so it's impossible to give precise instructions.
Chris