duplicate record created each time in customer > callcard relationship (1 Viewer)

I am creating an access database for recording calls and follow ups for a company

relevant tables
mst_customers
card_call

ID from customers and customer_id from card_call have a one to many with all records of card_call


although its more elaborate than this, lets get down to the problem

i created a form with a subform that should basically allow selection of customer and based on this, the creation of records in card_call as per customer selected. form and subform are linked by customer_id

everything is working except a peculiar issue where if i select a customer_id it shows all relevant records + an additional record (usually 1 or 2) that just changes the customer_id for that record.

Example

customer_ID = 2 (combobox bound to column1 and showing name/column2)

output
call_ID | Customer_ID
1 | 2
2 | 2
3| 2

changing customer_id to 4 will change to
1 | 4
(new) |

please let me know what i should be doing. I know the answer may not be so clear and maybe i can post my database here if anyone wants to have a crack at it.

of if this is a common problem, maybe there is a known solution

Thanks,
saud

I'm not (really) sure what you mean, but out of the description the combobox is a wrong chose if you bound it to your table.

If you want to select a customer_ID from the combobox and move to the record for that customer, then it has to be unbound. You also need some code in the comboboxes after update event.
Because if it bound to the table, you change the customer_ID from the value it has to the value you select in the combobox.
Below is a link to decription and sample code, how to setup a unbond combobox and move to a record.
http://support.microsoft.com/kb/287658