Maybe they were depressed and just couldn't get out of bed to send it. Or maybe the ship from China was behind. Inventory control is a big problem with seasonal demand items and I would guess the orders are flying in right now, it's right about the time of year where so many get so bad that they've gone to the doctor and gotten diagnosed and then ordered. I would bet you could plot the weather by their sales with about a 10 day lag.
Anyway the vitamin D deficiency is a big thing.
A Caucasian needs about 1/4 the time of exposure to sunlight that would turn the skin pink on a very regular basis to avoid vitamin D deficiency without supplements.
Negroes commonly need 5 to 10 times longer exposure. You can bet right now today the incidence of vitamin D deficiency among dark skinned Negroes in a northern city like say Chicago or Detroit among those not taking supplements is probably approaching 100 percent.
This is seriously implicated in a few health problems. Depression, osteoporosis, myopathy, hypertension, influenza, chronic pain, heart disease, thyroid problems, autoimmune diseases, and some others too. Usually due to the seasonal exposure people don't develop full blown rickets in the US, but it's common among those Muslim women who completely cover up before going out. It's acutally an unusual woman in those groups who is not vitamin D deficient.
And this deficiency and resulting depression actually causes people to do all sorts of things.
Like spring break in the south where you run around mostly naked and feel better than you have sitting in class in months. Or the winter vacation in the south for the same reason. Go to the tanning salon because you feel so good. And so on. Like most things people will overdo it. You don't really need to tan. Tanning actually increases the exposure needed. And tanning beds focus on the wrong type of UV light. For vitamin D you need UVB for tanning you need UVA. Tanning beds give off some UVA but you get a relatively high dosage of UVB.
A white skinned person needs about 20 minutes of exposure of their arms and face a day.
I'm not a big pill person, but most people really should take a couple of the combined calcium-vitamin D pill a day during the winter. We'd be a happier society if we did.
The SADD lights aren't really designed to give you the vitamin D production. You can get Vitamin D lights too.
The whole thing is, it's a fairly simple test to test the vitamin D level in the blood, but it's very seldom done. I would almost bet money that the SADD light was prescribed without even testing the level of vitamin D. Lack of sunlight produces both, presence of one doesn't exclude the other. But you can sit in front of a SADD light until the cows come home and if your problem is also a vitamin D deficiency, it won't be totally effective.
Sorry, about the rant. Just one of those things I've learned about over the years. It would be nice to find a doctor or two who practiced medicine but that's a difficult thing to do. Can't imagine how any physician would prescribe antidepressants without automatically testing vitamin D and manage to keep a medical license but that's probably why they are wealthy and I'm not.
Oh well, I guess they can't be up on everything. You should see the look you get when you tell them you'd like to test for the level of substance P in your brain.
I haven't gotten one to prescribe a substance P inhibitor either even though there are a couple on the market. Guess I'll have to stick to the Capsaicin for now.
Marv
It's probably from a southern state, where they are basking in the sun instead of sending me my light!
I mean that seriously....no joke. 
