I'm not sure who accepted RokuRey's response as a solution, but what a freaking joke!
Everyone before and after are telling you the post office does not accept the address, whether you think it is correct or not. Multiple people have mentioned the address that is being used and seems to get it there. Maybe one of those user comments should be an accepted work around.
An accepted solution would be Roku updating the address in the return instructions to what's accepted by the post office as users seem to think the accepted address is the new/updated address. If so sure the address is correct and up to date, then Roku needs to get it registered with the post office.
What should have happened a months ago is someone calling to the center or to the local post office there to ask about the address instead of this thread continuing to grow. Roku should be embarrassed.
But hey, if you think it makes sense to keep getting complaints for another year and saying a moderator's comment is an accepted solution, keep at it.