Has the baby ever taken a bottle before? It's a pretty big deal to get a breastfed baby to take a bottle, unless they start in week one or week two. So that would have been my advice to this mom planning to go back to work (which I did at three months, with all three kids) -- start early (which I didn't do, with my middle one).
But now this baby is three months, and has never taken a bottle? That's a really difficult job to throw at someone else! That poor caregiver! Believe me, that little one will protest like mad. I'm in agreement with the daycare. They just have to get so hungry that they eat! You can lead a baby to a bottle, but you can't make her drink. Just because baby wouldn't eat doesn't mean the daycare wasn't doing their best to comfort and help baby in a new situation. If not, I could be upset at them. But not because the child wouldn't eat.
With my middle one, the baby, the nanny and I were all in tears the week leading up to my return to work. With my son, we tried every kind of nipple, we tried pumped breastmilk. We tried a formula sample. I was seriously really to call the pediatrician to ask when I needed to bring him in for IV fluids. He would not take that bottle. Finally, we put cold water in it. That seemed to be what he needed to suck just a little bit. Once he got the hang of it, he would eat when he got hungry. But he never liked the bottle, and graduated very early to a soft tipped sippy cup, drinking pumped breastmilk. (he never would drink the formula, either)