Parenting advise please!

My daughter is 10 years old, her dad (my ex) got her a phone 😣

It doesn’t have a plan, and she can only text on it. Anyways, she told me her friends blocked her.

I looked at her phone and she will text them like 50 things in a row before her friends can respond. Her friends blocked her because they think it’s annoying and they tell her to stop and she doesn’t. She’s at school now. I’m trying to think of a good way to tell her to stop without making her feel bad. Any advice? Thank you all!