Batter Sticks to Fluted Bundt Muffin Pan?

I have a NordicWare fluted bundt muffin pan; and it sticks so badly it tear sthe muffins up when trying to get them out. I know I can use the baking cups, but then I don't get the pretty formation of the pan's muffins. I tried spraying with Pam the last time I used it, but it is as if I used nothing. I have not used the pan for awhile because my beloved hubby passed away and I haven't had the heart to cook for a long time.