It's funny. I've had my bank call me regarding "suspicious activity" due to purchases I made at supplement websites, but when two fraudulent charges were made on my account that totaled $600, I received no call whatsoever.
Bingo. It's about the payment processing company thinking they can dictate what can and cannot be bought wth visa, MasterCard, etc...
I got shut down on 4 sites in a row the other day. PH, peptides, eBay and finally kratom. It's like a form of non governmental control over the availability of certain things. Anything close to grey area... And they nail it. They don't want to be associated with anything that may be or become illegal. So they start investigation each charge and then you'll see an email from the vendor in a month "new payment processor, visa is back!" But it's overseas...
I got called once for stupid stuff. " Did you recently go to this restaurant"? Yes it's down the street for God's sake. Then I had to report a 500 purchase at a best buy in... Maine. I live in VA. So even when it's total legit they fail.