Sorry to hear you aren't in top form right now.
Had the same issue 2 months back - must have called 30 different supermarkets, Watsons and Mannings in a panic. Finally realized that there is a MeadJohnson hotline no on each tin - when I called to complain about their ridiculous supply issue, the lady on the line said that if were to become a "member", they could deliver 3 tins to my house within 24-36 hours! And that going forward, if i needed any, i could just call and have tins delivered!
I was livid! There clearly isn't any shortage, and appears that they are tinkering with their supply into the marketplace, drip feeding the retailers.
Apparently Enphamil has become the brand of choice amoungst Mainland shoppers and i feel they are deliberately making it scarce in the shops to make it seem more exclusive and hard to get. Indeed when i went to Jason's and Park n Shop today, there was none to be had. It's ridiculous! Seems like such a scam making it so unnecessarily stressful.
Apologies for the long post/vent...sadly i have no choice but to be a customer as my baby takes well to their foumula. So call them first thing in the morning
on 25106321. All the best!