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I am sorry to hear you are experiencing issues completing your purchase. I know this must be frustrating. Based on what you have explained, it sounds like you may be having issues with our internal security system when trying to send a payment.
I would suggest you clear your cache and cookies, or try again using an alternative browser. Sometimes the system just needs time to reset.
If you continue to experience this issue, please contact our Customer Support. To contact us, simply click here. Alternatively, you can contact us via Facebook https://www.facebook.com/PayPal or Twitter @AskPayPal.