I was googling for hours and days, how to deploy correctly an ASP.NET MVC app using Twilio,

I tried to deploy it using IIS Manager on my local PC, everything works great, except one thing, that when 2 people are calling in the same Twilio number, the app is dealing with the callers as is it all the same person, for example, when someone calls in the system retrieves the information based on the number called in and then process the current user, and when a second number calls in the same time he will go through the others account.

I also tried to deploy it to my website hosted on Fasthosts, but with no luck, i contacted Fasthosts, and they don’t know what i want from them.

Please guide me what I’m wrong and how to do it correctly.