The reason is pretty clear, the worked remotely and so had no means to physically reach out but instead had to wait for people to reply on mail.
The company needs to take at least partial blame here.
Note that I am not convinced that this is the case here - I simply don't have enough information to make the judgement.
Wat?
My other thought was to file blocking bug/defect issues on the relevant software because obviously if it can't build in the first place it's certainly not passing QA.
Some of this may get to the level of passive-aggressive or aggressive-aggressive bridge burning.