Sounds like I have been fobbed off with a generic response too! Doesn't sound like they even looked into it! "Thank you for contacting PayPal Merchant Technical Support. I apologize for the frustration with your payments. When you are using website payments standard add to cart buttons like the ones that you are using, the intended behavior of the add to cart button is to take the buyer to the PayPal cart page. From there your buyers can either checkout, or click the continue shopping button to go back to your site to keep adding stuff to the cart. Now that being said, if your buyers are using a browser that does not support cookie use, then the cart will not accumulate as it should. Another additional note, is that if you have multiple buttons in different currencies, then adding two different items of two different currencies will break the cart as well."
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