Customers address replaced with ours on local pick up

[renascentColleg]

Hi, when a customer checks out and selects local pick up as the delivery option, all the customers address details get replaced with ours, we have no way of knowing where they really are and often local pick up is an error, I can then no longer create a postal fee request as there is no address other than ours to ship to, it overrides THEIR address in the back end. How can I stop this happening please