In a company, after the product has gone live, somehow the development distribution email has been given to the end users (who happen to be the company's call center) who contact the development team directly for queries and questions on bugs or for high priority defects (not critical though). Also, the IT support department is raising tickets from the end users and contacts the development team directly.
The company is working is doing scrum, there is a SM and PO, and the teams have their normal iteration cycles. What is the best and most efficient way to prevent outsiders contacting the development team for the queries?