are the offers with credit card details truthworthy?

hello admins
i am little worried about giving out my credit card details in "free to try" type of offers
so i want to know if anything can be done by the admins to ensure that we are not charged from such offers and if we get charged then the admins can help us get our refunds if proper proofs are provided by us?
i recently submitted my creditcard info to this site http://megaflix.net/ and yet i have not received my rewards for it and neither i can login to their site and when i googled the site i got this http://scamhunter.com/2011/scam-alert-megaflix-net/
the comments suggests that they charged them $50. i don't want to be charged $50, i have just earned $4.
hope to get the reply from admin/mon soon
thanks

roshanrbb and yet i have not received my rewards for it

Please submit your proof of subscription / order to [email]admin@gptreasure.com[/email] and mention your username and the offer name that was not credited (only Credit card offers can be sent by email), and we would approve this offer for you if it is genuine and made through our site.

Thanks!

gptreasure and mention your username and the offer name that was not credited (only Credit card offers can be sent by email), and we would approve this offer for you if it is genuine and made through our site.

Thanks!

right after i submitted the 2nd page info, the website redirected me to another page requiring a video player and i downloaded it and installed it and guess what, it closed all the browsers and when i opened it, the survey page said you didn't come from proper valid address, click here to go to the start page. and when i went to my email, there is no sign of megaflix emails.
and from the scam report i posted above, i am worried about the charge. i am going to change my card surely!