The Coca Cola Kid[1985]

Becker, a hotshot American marketing executive (played by Roberts) from The Coca-Cola Company, visits their Australian operations in Sydney and tries to figure out why a tiny corner of Australia (the fictional town of Anderson Valley) has so far resisted all of Coke's products. He literally bumps into the secretary (played by Scacchi) who is assigned to help him. Becker discovers that a local producer of soft drinks run by an old eccentric has been successfully fending off the American brand name products. The executive vows an all out marketing war with the eccentric but eventually comes to reconsider his role as a cog in Coca-Cola's giant corporate machinery. Along the way there are humorous subplots involving the office manager's violent ex-husband, Becker's attempt to find the 'Australian sound,' and an odd waiter who is under the mistaken belief that Becker is a secret agent. (from Wikipedia)