I have fed feeders that thawed once and were re-frozen with no ill effects noticed so far. A lot of people will go so far as to place a feeder in a cage over night and if it's not eaten by morning they re-freeze it and try it again at the next feeding. At that time if it's not taken they then throw it out.
Is it the best practice, I'd say no but once in while I belive will not hurt them. Think of some of the stuff they eat in the wild.
In your case they never even left the freezer, they just got cold, not even warm.
I wouldn't worry about it.