Can't charge nx trough credit card

I don't know if it's old, but I couldn't find an answer when I used the search option, my problem is that after I bought 5k with my credit card ( the only one I use to charge nx) I can't buy more nx, I keep getting this message: "Credit Card Error: We're sorry but your credit card was declined. If you feel this is in error, please contact us."
I don't know what to do, I've been trying for 1 hour but nada, I do have credit on it, so I dont know what it might be.

You could uhh...try contacting them? Like it says? >_>

I did, they told me to wait. Nothing happens.

I'm having this issue lately too. It happened after I charged some nx, and then it didn't work again and gives me the message you're getting. My Credit card is perfectly valid and I even bought something with it in a store to make sure. I maybe thought it was the nx credit limit there apparently is per month, but I think that gives a different message, telling you that you've hit your limit.

Same thing happened to me awhile back, Nexon's billing system is really really picky. I would suggest either using PayPal or buying Ultimate Game Cards online.

Same with me here. Meh guess just wait a little bit.