AngularJS not writing $scope variables to view - angularjs

Question

I have a very strange issue. Using AngularJS 1.5.8. With previous versions it didn't work either. Functions like ng-bind, ng-model, ng-submit work fine.
Click on "Inschrijven" http://adr-opleiding.ismiami.com/, second step "Postcode" and enter e.g. 1000. It will display Amsterdam. I used a div element w/ ng-bind="city". If I use {{city}} it will always display {{city}}. I can't get it to update from a controller.
angular.module('app', []).controller('HomeController', ['$rootScope', '$scope', '$stateParams', function($rootScope, $scope, $stateParams) {
$scope.$on('$viewContentLoaded', function() {
$scope.app.settings.htmlClass = $stateParams.htmlClass.website;
$scope.app.settings.bodyClass = '';
});
}])
.controller('WizCtrl', ['$scope', '$http', function($scope, $http) {
$scope.city = '';
$scope.printCity = function(){
if($scope.postcode.length == 4) {
$http({
method: 'POST',
url: '/db/get.php',
data: { action: 'retCity', zip: $scope.postcode }
})
.then(function success(response) {
$scope.city = response.data.city;
}, function error(response) {
});
}
}
}]);
And here's the HTML:
<div class="form-group">
<label for="wiz-postcode" class="col-xs-4 control-label">Postcode:</label>
<div class="col-xs-3">
<input class="form-control" type="text" name="wiz-postcode" id="wiz-postcode" style="width: 80px;" placeholder="Postcode" ng-keyup="printCity()" ng-model="postcode" onblur="this.value=this.value.toUpperCase()" />
</div>
<div class="col-xs-5" ng-bind="city" style="padding-top: 8px; font-size: 1.1em;"></div>
</div>
At the very top of the HTML I have a div element w/ the controller:
<div ng-controller="WizCtrl">
So the question is how come that $scope variables work fine for everything except updating the view w/ a variable like this {{test}}

Answer 1

A new Google search "angularjs variables in braces not working" got me to AngularJS-Twig conflict with double curly braces from which I learned that w/ AngularJS you can set the symbols w/ the variables start and endSymbol
var app = angular.module('app')
.config(
[ '$controllerProvider', '$compileProvider', '$filterProvider', '$provide', '$interpolateProvider',
function ($controllerProvider, $compileProvider, $filterProvider, $provide, $interpolateProvider) {
app.controller = $controllerProvider.register;
app.directive = $compileProvider.directive;
app.filter = $filterProvider.register;
app.factory = $provide.factory;
app.service = $provide.service;
app.constant = $provide.constant;
app.value = $provide.value;
$interpolateProvider.startSymbol('::');
$interpolateProvider.endSymbol('::');
}
]);