Hi, I'm Lori and I'll be helping you today. I'm sorry to hear you're having a problem. Please bookmark this page so you can get back to it easily. What is it you are trying to do here? Activate mobile texts? In order to text the letter F to 32566 you should be able to put 32566 in the To line of the text, as if it was a phone number. Then just put the letter F in the message area, without quotes around it, just an F.
If you are trying to sign up for Facebook mobile, you need to go into your account settings and select mobile on the left. Make sure your mobile number is XXXXX with Facebook. Then go here and sign up for facebook mobile. You'll need to select your carrier. https://www.facebook.com/mobile/