My friend worked on the phones for years before he transitioned. When most girls talk on the phone they go higher in pitch but they also exaggerate the highness on certain words like 'hello' and at the end of sentences. I guess to sound polite, anyways he did that because everyone around him did and when he started T he still automatically just went high before he realised he was doing it. It took him ages to break out of the habit and become more monotone but since he has he always passes on the phone. So maybe for some of you it's not your voice but the way you talk?