According to Department of Health's guidelines: you can keep defrosted milk in the fridge (4C) for 12 hours.
So, if the temp of your opened door freezer is < 4C, it should be ok!
In this case, what you could do is to give the frosen milk to your baby until the stock finished since they can't keep long. On the other hand, you should keep pumping and store the milk in the fridge properly.