I sold my iPhone 5 on eBay, buyer was from Russia. I know red flag, but they paid immediately, so I rolled with it. I sent the phone out via USPS priority international, with insurance and tracking number on 9/30. Quoted shipping time was 6-10 business days. Per the tracking it still has not been delivered. The buyer has opened a case with Paypal, and Paypal has put a hold on my account. I called USPS and opened a case to track the package down. Per USPS, once the package hits customs, the tracking information might be delayed or sometimes not updated to show it was delivered. I'm worried that the buyer was counting on this and I won't be able to prove that the iPhone was actually delivered. What are my options? I have the IMEI of the iPhone, is it possible to blacklist the IMEI so they cannot use the phone?