The US Post Office is the stumbling block as to why Tower cannot send you the kit.

In fact most of the Postal Services from around the world will not accept kits this size as airmail.

It's just too big for the airlines to carry as airmail in the specialised cargo containers that fit inside the cargo holds of airliners.

Unless you know someone who is travelling o/s and can bring one back as personal baggage, (though it seems odd that one can be checked in as personal baggage to be carried on an airliner, but not posted. Then again, you and I don't make the rules.)
or are prepared to fork out the mega bucks to ship one in via Fedex, you are stuck with the wait.

Don't fret, your not the only one caught out by Dawn Trading. (One day it may "Dawn" on them that there are such things as customers out there!)