(EDIT)dd has said, and Gary confirmed in PR, that GZ is going to offer incentive programs to get subscribers, like me, back into the fold. If they lay it on the line, explain what had went wrong and how it has been corrected, it may work. But to just throw a free month, or reduced rates out without explaining the problem and the fact that things are better, will not lure me back. Burned once, burned twice, never a third time.
EDIT: Just thinking, maybe explaining that things are better, and offering a free month long trial to prove it, might work. Throw in an upgrade to 4 per month at the 3 price and I'm sure it would work.
The upgrade alone would help turnaround problems.