Chart Group does not work

I want to make a simple chart based on two fields one is a user name the other is a number.

People fill out a form with their name and a dollar amount in another field. I want the chart to sum all of the dollar amounts for the user name.

So combine all user names on the x axis and sum the dollar amounts on the y.

For example, Data would be as follows:

User             Dollars
matt            2000
matt            1000
matt            500
dave            200
dave            5000

Chart would show:

matt ============== 3500
dave ============================== 5200

Problem is i cannot get the users to combine into one.

The chart ends up looking like this:

matt   ========================= 2000
matt    ============ 1000
matt    ======   500
dave    == 200
dave     ===================================================== 5000

all items are separate. How do i make this work? I have set up grouping but it has no effect
would the fields be case sensitive?

thanks

chart would look like the following