My name is [your-name], I am a member of the business development team at [your-business-name].
I see from our records that you recently completed a demo request from our website [your-website].
As I was unable to contact you on the phone number you provided I wanted to send you a quick email to introduce myself.
Please let me know when we could schedule a short call in the coming days and what number I could reach you on.
Looking forward to your response.
Business Development Manager
Direct : +[your-phone-number]