The move is 'another nail in the coffin,' Reepher CEO says. Marking another setback for the marijuana industry, Mastercard recently sent cease-and-desist letters to banks and payments processors that assisted in the purchase of legal cannabis.In the letters, the credit card giant told the recipients to suspend accepting marijuana transactions using PIN debit cards on its network, according to a July 26 Bloomberg report.Mastercard did not respond to Kiplinger’s request for comment.For an already-