Report Live accounts over a time period

Hi, 

I am looking at trying to establish how many live accounts we have over a period time. 

The variables are:

1. Contract_In

2. Contract_End

3. Customer_Name

4. Total_Value_spend

What it is I am trying to show is a table that has the 3 variables (Date, Value and Volume) based on the above variables.

1. Contract_In - Date the customer joined        2. Contract_End - The date the customer left

So if the date is Jan-18 and we have 500 live accounts that's what I want to show

Feb-18 we have lost 5 but gained 20 so I need the table to show 615 etc

Note: If an account was live Jan but dropped of in say April, I still want that account value and volume to show in Jan Feb and March. I hope this makes sense.