Hi basically I have 1000s of customers who don't have addresses in magento (22.214.171.124) that were imported previously.
I go into dataflow profiles, export a specific customer (as a test) so I have a CSV layout and then paste into the columns the data for the customers and their addresses to import back in.
What I want is to basically amend these customers with new addresses I have in another CSV.
I exported a customer and pasted in the address into the billing and shipping columns and used data profiler to import it back in.
However the problem I am having is that it is creating a duplicate customer and not amending the current one.
Can anyone suggest why this may be happening?