i had the same problem. i spoke to a guy at the retile expo in homebush and he suggested this
-defrost your pinkie and warm it up
-boil the kettle and pour the boiling water into a small bowl
-dry the pinkie off and hold its head and head only in the boiled water for 10 seconds
-dry the head and quickly offer it to your stimmie
this makes the head 'glow' hot and it attracts the snake to them more. i did this with my wheatbelt stimmie, she hadnt eaten for nearly 10 weeks, as soon as i did this BANG she hit it harder than ever and has not refused a feed since. i was so greatful for this piece of info and will use it again in the future if i ever have the same problem. also try offering late in the afternoon, look for some signs from your stimmie like when its head is sitting just at the front of its hide. waiting for dinner kinda thing. just gotta read your snake a bit mate.
hope that helps. dan