NSArray *array = [[NSArray alloc] initWithObjects:@\"ΕΛΤΑ\",
@\"ΕΛΤΑ COURIER\", @\"ACS\", @\"ACS ΕΞΩΤΕΡΙΚΟ\",
@\"DHL\",
You need to add NSNull class and the best way to do it is like this:
NSArray *array = @[ @"string", @42, [NSNull null] ];
I personally recommend to use a specific value like 0 instead of null or nil in your design of your code, but sometimes you need to add null.
There is a good explanation from this Apple reference.