Gazpacho, I'm sorry you're in the position to have to deal with this garbage. You're probably not the only one out there who is concerned about fraudulent online pharmacies. I'd scour through the forums online and see what others are saying. As long as you're not looking for a controlled medication, you shouldn't have a problem buying the drug in another country.
Failing the Canadian mail order option, I'd call up a pharmacy at the nearest Mexican border city from where you live, see if they carry it, and then I'd get take my passport, get in the car, take the bus, or whatever, and go pay them a visit. If you've got a doctor's prescription, you're okay. It's definitely worth it if you can save thousands of dollars.
When Tijuana was going through a dangerous phase several years back, I had friends bringing me migraine medication from France, Turkey, and Thailand. No way am I going to buy medication in this country and add to the massive profits of the pharmas. As for my mother's dementia medications, the directors of the memory care place where she was said they couldn't administer them if I brought them in from the outside. We had to pay over $3000/month until I got her on Medicare Part D, but then she passed away.