Oracle don't want to get more customers?

Oracle don't want to get more customers?

My friends and I have normal credit cards that work on every site, or want to pay through PayPal, which is the most accepted way today, or we have prepaid cards that all the other sites also accept

Only here they don't accept them. I don't understand why. I also don't understand why these cards are not accepted here. What is their problem with accepting them?

There is real money in them that can be used for transactions, here it is just an account that is always free, so why do they care about receiving them? I'm not trying to do any scam just use always free account