Marijuana News July 7, 2012 Credit Card Transactions Canceled at California Medical Pot Dispensaries Lakota The Feds have informed credit card merchant service providers that they must no longer process medical marijuana transactions or risk losing their relationship with Visa and Mastercard forever. Read more about it at NBCBayArea.com. Tags: credit cards, Feds, medical marijuana dispensaries, Treasury Department. By: Lakota. Permalink: . Paul I guess it is time to start using BitCoins!