This update/rollback was a disaster. Everyone lost something.
I personally struggled for two days trying to adapt and understand this new topology and even had it working. Now I wake up to find that the guts have been stripped out of my project. It was a COMPLETE rebuild of its predecessor using the new upgrade which we had no say over whether we got it or not.
Now I'm afraid to proceed, or should I say start over again. You are making enemies of your own customers.
Might I suggest that NEXT rollout be in the format of 'choice'. Give them two websites to choose from. Let them continue their current projects in the OLD format if they so choose. Or, if they want to be beta testers, allow them free access to the new site while your work the bugs out. Then, over time, as people complete their OLD projects, make the NEW technology website mandatory. At least it will allow more time to test in a live environment without effecting so many people.
This was so wrong. Damage like this, you simply cannot just apologize your way out of. That fixes nothing.
I suggest releasing a statement that reinforces your next plan of action. Something at will reassure everyone that this will never happen again.
I want to sing praises about appery.io and how great it is. But cannot as long as such things are occurring.