The customs tracking # only gets you as far as the last stop in the US, though. It does't show the progress after that (at least, not on the one I just checked, one that I know arrived at the final destination) so all you would know is that it got as far as (I assume the last stop is...) customs. :( But is still shows you upheld your end. I also have had a package (coming to me) from Canada get held up in customs. Wound up being almost 8 weeks, if I recall correctly. I had nightmares that they were ripping apart each pony looking for hidden drugs.
Since she's being nice, can you get her to agree to a refund ("since your first package hasn't arrived, why should either of us take the chance on another one" would be my reasoning; maybe she has the same thoughts...?)