I got the same problem!! I feel your pain!! Here chat transscript I had with Live Chat Support
Hi, my name is Deepika. How may I help you?
Michael: I can't buy Fifa points from the Store on PC
Michael: I tried with paypal and creditcard, both are not working
Michael: This error comes: An error has occurred while trying to process your request. Please, try again later.
Michael: And its been like this for 5 days
Deepika: Please provide me your email address that you are using.
Michael: I purchased fifa points a week ago and it worked good. Now it doesnt anymore.
Deepika: May I know from where you are purchasing the points?
Michael: From the web-app and also tried ingame
Deepika: Please allow me a moment.
Deepika: I am so sorry for the delay caused in responding
Deepika: Please stay online I am still working on your issue
Deepika: May I know the browser you are using?
Michael: I'll be waiting, no problem. Hopefully the problem can be fixed
Michael: I'm using firefox
Michael: Should I try with Chrome or internet explorer?
Deepika: Please try clearing cache of fire fox by visiting this link :http://support.ea.com/app/answers/detail/a_id/1126
Michael: Ok, I cleared the cache
Deepika: Now try to purchase the points.
Michael: Still the same..
Michael: General Error
An error has occurred while trying to process your request. Please, try again later.
Deepika: Try using any other browser.
Michael: It's also not working in Google Chrome and Internet Explorer, same error messages
Deepika: Sorry to hear that.
Deepika: Please provide me the screen shot of the error you are getting .
Michael: Ok ill give you 2 screenshots
Deepika: Let me check.
Deepika: I'm sorry to disappoint you in this that servers are facing some technical issues for your region so you are unable to purchase the points.
Deepika: Our engineers are working on it.
Michael: According to this topic on EA forums there are alot more people with this problem.http://forum.ea.com/uk/posts/list/1038478.page
Michael: Anyway, I guess I'll have to wait till you guys have a fix
Michael: Thanks for your help
Deepika: My pleasure.
Deepika: Is there anything else I can help you with today?
Michael: No not really, but do you know how long this is gonna take to fix?
Deepika: I am sorry I can't assure anything now.
Michael: Ok thanks, byebye
Deepika: Thank you for your participation. Have a wonderful day.