What is the expected processing time of a phone return and refund?

I returned the Xfinity mobile phone within 14 days of ordering. The device arrived at the warehouse as expected according to the tracking. Surprisingly one week later I received an email from Xfinity mobile that stated, "we haven't received your device yet" and reminds me of sending it, which makes me concerned. I called customer service and was told it's graded already two days after arrival. Why does the system send me such a reminder email if the phone has been received and worked on? It's conflicting info given to customers, which one should I believe? How many days are the expected time to have it removed in my account and complete the refund since the return is initiated or received? Thank you!