How should i tell her i want to break up if she dont answer.me..?

She never answers.any of my calls no more she.doesn't call me amor no more I feel her love for me has gone and it hurts me because shes my first gf and I love her with all my heart she just don't answer any of my calls any more or any text how should I tell her should I write a letter should I text her that what should I do?