Exporting then Importing the form was the thing that worked for me.
Had the same issue as described in several other topics here. Namely, the CC list wasn't getting updated even though the plugin recognizes the CC login credentials as correct and mapping was correct.
Tried many classic trouble shooting steps: toggle GF plugin and GF Constant Contact plugins off and on; created new form by duplicating existing form, created new CC list, with no success.
Then I exported and imported the form and it worked. Hope this helps others.
Oh - and I want to thank the plugin developers for making this valuable add on and for all the blood sweat and tears involved in supporting it.