When we turn the zone tv on a padlock shows and we...

Question

My son was pushing the 'call' button on the remote to display the time. He pushed it repeatedly and then a red padlock came on the blue screen in the bottom left. Am now unable to do anything on tv. Have tried all remote buttons, plus buttons on tv, and also tried unplugging from wall and then reconnecting, but to no avail.

Have only had the tv for 1 week after purchasing off trade me.