My MMF has the consistency of chewed gum almost! This is my first time to make/use anything other than Wiltons (:S) so any advice would really be appreciated.
You may have added too much powdered sugar. When finished it should be very much like Wilton or any other fondant.
Take a small piece and knead in a bit of shortening and see if that helps.
For future mmf, it will usually NOT require all the powdered sugar listed in the recipe. when the dough is soft but no longer sticky, stop adding sugar.