Frankly, i don't understand exactly what is means "Servile"

Frankly speaking, I don't understand exactly what "Servile" means.

I wrote Servile official letter to our customer in situation with our failure products.

I wrote an official letter to our customer about  the situation of our product failures.

My daughter show me servile letter what when she is angry, she doesn't shout out loud to mother any more.

My daughter writes me a letter when she's angry, she doesn't speak out loud to her mother anymore.