Hi,
I have hands on experience of Twilio integration for SMS and Video Calling and used SendGrid for email management. My experience with both platforms make me best fit for your project as I have over 10 years of development experience in .Net & .Net Core technologies (Web Forms, MVC, Web API, WPF, WinForms) using C# and VB.NET.
Lets discuss more details in inbox, looking forward to hear from you soon. Thanks
Ahmad