honeymunk and pinklotus~~Welcome to the forum!
The best cupcake liners are labeled GREASE-RESISTANT or GREASEPROOF. Wilton and other decorative paper liners are cheap to manufacture, and end up looking cheap because the colorful designs end up getting muddied by the grease in the batter. Paper liners also present a whole host of other problems.
If you live on the West Coast and have a Smart & Final nearby, you can purchase 500 of these liners (photo below) for about $6. These are fabulous and will never let you down. Reynolds foil liners and other GREASE-RESISTANT/PROOF liners are also excellent, but they will be more expensive.
Try better quality liners and you will probably notice that less cake sticks to the liner.