is the username the server host assigned you and the password is the password the server host assigned you.
In your case, horseracingforprofitonline.com is either your own domain or one that belongs to someone else. Whoever it belongs to was either informed by the host of the domain what the FTP username and password are or they themselves established a username and password for you to use. The passwords are case sensitive by the way and if the password was Green then GREEN or green or anything else than Green would not allow you to log in.
They would also have informed the domain owner what the FTP server was and that, in your case, would normally be ftp.horseracingforprofitonline.com using port 21 (www.horseracingforprofitonline.com or just horseracingforprofitonline.com would not work as they are not the FTP server the account and password are for).
Thus you should see that in regard to your comment "the only thing that I can think is that my user name is not the name that I am subscribing to your service with, how do I change that so that it is the same as the one used by my hosting company." your CNET username and password have NOTHING to do with your hosting company or using fileZilla.
I have been having a great deal of trouble, as I keep getting this message every time I try to connect.
Status: Resolving IP-Address for horseracingforprofitonline.com
Status: Connecting to 18.104.22.168:21...
Status: Connection established, waiting for welcome message...
Response: 220 ProFTPD 1.3.0a Server (ProFTPD Default Installation) [22.214.171.124]
Command: USER horserac
Response: 331 Password required for horserac.
Command: PASS **************
Response: 530 Login incorrect.
Error: Could not connect to server cannot log on to server.
I have been intouch with my hosting company, and all my details are correct, the only thing that I can think is that my user name is not the name that I am subscribing to your service with, how do I change that so that it is the same as the one used by my hosting company.or can you see something that I should be doing, please help, as this is driving me crazy, i've been at this problem for around 5 days.