OK, there are still mismatched braces in there (you have two closing ones before that else statement) which will cause problems.
Also, if the queries are never run, you'll get an error for attempting to use variables that haven't been defined in your if statement at the bottom.
Lastly, you don't have any validation in this at all, just a check to see if a variable equates to true, which it will either always be, or you'll get an error, so the else part will never ever be run.
You need to validate your data before trying to use it in a query. Go through each $_POST variable that you plan to use and check to make sure it's something you expect. Use mysql_real_escape_string() to create variables that are safe to use in a query, or in short order you'll find yourself hacked by someone looking to have some fun.
Also, you should move the $mod= and $plan= lines to inside of the first if statement, otherwise you'll get another error if the script never receives those $_POST values.