Iphone Trade In

I ordered a new iphone under the recent trade in program for the iphone 12.  I received the new iphone on Oct 23 and received an email saying that the return shipping materials for my old phone would be received in 4-7 days.  It is now Nov 3 and I still have not received the trade in shipping materials.  The support phone number goes directly to a busy signal and the chat function on the support line for trade in phones does not respond even though it says an agent will be available in 2 minutes.  Getting very frustrated.