My son will sometimes tell me that certain friends of his say to him that they are not his friends anymore. It breaks my heart and then I sometimes hear that some of these "former" friends have hit him. Well, I decided to speak with his head-teacher. She had no idea that he was hit, as she was not there at the time. She did say the children usually tell each other on a day-to-day basis if they are friends or if they aren't friends. Some children just might be cranky at the time and not want to play and can only express that they don't want to be friends, rather than "needing space today". So I hope your daughter's other classmates decide to warm back up to her. I'm sure its definitely not something she has done.
We all tend to know that our child must be loved by all, but there are some kids out there that are a not as nice as our own and therefore we are baffled by what is going on.
You have the right idea by speaking with the care provider. But just don't do it infront of the children. Just simply talk quietly while everyone is playing and not paying attention...and never accuse any child or point out who said what, that child may hear you.
Like I said, some times the children need space but can't express it so they say the easiest thing like "you're not my friend anymore" then again some kids change and are never the same person. Encourage your daughter to continue to play nice as she is and I'm sure those kids will come around!
Good luck, P.!