Hi Alex,
I'm honestly not sure anymore if it's still feasible to re-enable your application at this point, as we are in the last steps of the deprecation of Master/Slave datastore.
At this point your only shot (and this is not even a sure one, you might get a negative answer anyway) would be to contact support. You can do so using
this form, but be aware there is a risk your application is inaccessible even for support.
Good luck!