I just finished using the free $25 dollar Media Hub gift card that came with my tablet. I went to enter my credit card number and it keeps telling me it's invalid. I tried over and over again. Even called Samsung (no help) Is this a glitch? Has anyone else had this problem? No matter what card I use it says invalid card number. They are valid. I love Media Hub and they are having a $.01 sale right now. I need this to work. What can I do?