They always sent me a canned standard response when I contacted them (see below). I have tried all of those things and also tried different things at my end

1. Tried it on a different device/incognito mode
2. Played around with the document number digits
3. Changed the language at the processing page to Argentinian, Brazilian and Paraguay
4. Didn't use google translate
5. Used multiple credit cards
6. Tried VPN'ing to Brazil and Argentina

None of this seems to work. Surely someone on this website should have had some experience with this. Can someone shed some light on this? I have a feeling that it might be the visa card number I'm entering but I have no way to know.

Below is their email.
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Make sure you have entered your card information correctly: all the numbers on the front and the security code, which is on the back above the signature panel and is three numbers.

If you verified that the information you entered is correct and you still cannot make the purchase, if you use Visa, call (011) 4379-3400, option 2 and let them know that you are going to make a purchase online, they will ask you which store and for what amount. Wait 15 minutes and try again. If it is another type of card, find the contact number on the back and perform the same operation.

You also need to verify that you have enough limit to make the purchase, otherwise you will not be able to pay. We recommend that you use another card that you have available or that you change your PAYMENT METHOD.

If after performing the previous steps the problem continues, use a different email than the one you are using.

The only alternative channel for purchase confirmation is telephone sales, calling from your cell phone to *3000, the cost of the call is 14 ARS per minute + 800 ARS per passenger management cost.

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