First, there is no way in which you are going to be refunded for what you have bought since 2016!!! Especially since your post is about MM not recognising your keyboard.
Also, please do not use potentially offensive language in your posts; I have edited yours in this thread to remove such language.
However, coming to the details of your question, first please give us a screenshot of the File>Settings>Program settings>Audio/MIDI tab. We particularly need to see the Audio Driver and MIDI Input and Output settings.