To go back to FTM 2012 all that is needed is to open the copy of the 2012 database using the 2012 program that you created before you upgraded.
If your problem is syncing with Ancestry, I would wait a couple of days, until Ancestry gets their act together. I do not have an online tree and I am having trouble getting information from Ancestry as it has been extremely slow and long halts the last couple of weeks.
Possibly Caused by all the new 2014 users trying to sync to their old online trees?
So your problems may not be with 2014 but with the connections to Ancestry. Note FTM checks Ancestry as part of the start up operations.