Amazon seller wants my order number** to upgrade my device's warranty for free?

Good evening, I ordered two low-end tablets from Amazon. I've now received two emails from both sellers, telling me to send my order number to an email address so they can extend my warranty for free, one for two years and one for life. The attached PDFs don't seem very reputable, but I'm wondering what…

I haven't received an order confirmation or order number from Purelei, what should I do?

Hello, I ordered jewelry from Purelei on November 14th. It has already been delivered to me and I paid via PayPal. However, I have not received an order confirmation by email, nor is the order visible in my customer account. So I don't have any order number. The customer contact has not responded to me…