Though I've only ever met one girl who was ever called
Mel, and her name was
Melanie. This
Melissa's family pronounced her name Me-LEE-Sa, who knows why? She always pronounced it
Melissa, the regular way, probably because she knew it was a losing battle to insist that people call her by her family's pronunciation. I think
Melinda might have been called
Mindy occasionally, but not in general.