Horizon Gold Card is not really usefull for me?

Asked On Horozon Gold card
I was trying to lavel mu credit score when I got the email with information on www.horizongoldcard.com .Is it really useful to correct my score?

I came to know Horizon Gold card is prepaid card to make your Credit score better.
Its cost high and you can use it on their sire only.
You can think just spend all the money on useless thing to correct your score.

Also anyone know what is number of Horizon Gold card Customer Service?