No return label in my Trade-In kit

You need to contact Apple store support.

You can start here:

Contact Apple for support and service - Apple Support

Good luck!

whitebaek wrote:

I've got the trade-in kit but there is no return label in it.

I also checked the underneath on my address,

but no luck. What should I do ?

Call Customer Support (800) MY–APPLE (800–692–7753)

You may have received an email on the same date when you opted for a trade-in, as shown in the pic below