Perhaps you could provide some more details. How many messages have you sent and when did she stop responding?
It sounds like you have been sending multiple e-mails and made several phone calls. Unless there is an absolute necessity to contact her you need to stop this.
She will interpret your constant attention and 'interrogation' of your mutual friend as pressure. No need to necessarily go dark at this point but you do need to back way off and give her some space. Let her contact you.
Please accept this is going to take some considerable time. Are you prepared for that?
