Работаем с Customer ID не именами пользователей. Попробуй по аналогии.

RewriteEngine On

  RewriteCond ${lowercase:%{REQUEST_FILENAME}} ^/(m)-([0-9]+)/$
  RewriteRule ^/(.*)-(.*)/$  /?custId=$2&page=Business-Features-Map [P,L]

  RewriteCond %{REQUEST_FILENAME} ^/([0-9]+)\/([0-9]+)/$
  RewriteRule ^/(.*)/(.*)/$ http://url.com/?page=Business-Customer&custId=$1&headingCode=$2 [P,L]

mod_userdir

# UserDir: The name of the directory that is appended onto a user's home
# directory if a ~user request is received.  Be especially careful to use
# proper, forward slashes here.  On Windows NT, "Personal/My Website"
# is a more appropriate choice.
#
UserDir "My Documents/My Website"

#
# Control access to UserDir directories.  The following is an example
# for a site where these directories are restricted to read-only.
#
# You must correct the path for the root to match your system's configured
# user directory location, e.g. "C:/WinNT/profiles/*/My Documents/My Website"
# or whichever, as appropriate.
#
#<Directory "C:/Documents and Settings/*/My Documents/My Website">
#    AllowOverride FileInfo AuthConfig Limit
#    Options MultiViews Indexes SymLinksIfOwnerMatch IncludesNoExec
#    <Limit GET POST OPTIONS PROPFIND>
#        Order allow,deny
#        Allow from all
#    </Limit>
#    <LimitExcept GET POST OPTIONS PROPFIND>
#        Order deny,allow
#        Deny from all
#    </LimitExcept>
#</Directory>