Why do you need to cancel? Unless you can show 3 that the service is unusable you will be stuck with a cancellation fee. There have been a few posts from people who have been allowed to cancel early without charge. If you can convince customer services to agree to a no fee cancellation keep records, transcripts, etc as the whole deal seems subject to returning the router and 3 don't seem to provide the return label in time.
Best of luck.
