I believe the standard strategy here is to say you've been in an accident, you're in the hospital while traveling, your jaw was broken, and that's why you sound different. Or you're having the nurse call them. Something to explain why your voice isn't what they expect.
This happened to my grandmother a few years ago, with somebody claiming to be me. Purportedly, I had broken my arm in Spain, and needed money for surgery. Fortunately, she had the good sense to call my parents and find out if I was actually in Spain.
