Mtn mess up

I app**** online with mtn for a contract for a blue huawei psmart phone unfortunatley a black phone arrives .... i then enquire that its the wrong phone .... i called mtn got the run around finally got through an agent who says this matyer could take between 2 to 3 weeks to be solved .. how should a customer be pebalised for mess up from their side .... this is un acceptable .... i humbly request this matter to be resolved as a matter of urgency thanks