Drop Down Boxes Problem

I have 2 drop down boxes.  DDL1 and DDL2
DDL2 get its filtered data from the postback of DDL1.  More specifically DDL1 is a list of customers and DDL2 are Customer Contacts (which can be many).
I have the value of DDL2 copy over to a textbox (TB1) where I am using that to send the value to a database.
It works to a point.  
On initial Load it does fine and DDL1 shows a default selected value  of "choose one" and DDL2 is empty showing that null value in TB1.
Problem # 1
Once I pick a customer in DDL1, the  DDL2 populates but show the first record as default with still a null value in the textbox where I need it to show the selected value on the first defaulted record.  I am forced to choose another and then go back unless there is not other contact in which case I am gridlocked.
 
Problem 2
If I pick a customer  (DDL1) and contact (DDL2) and then go back a ...