I try to remove a contact from lists and add to another list, but I just get "Contact Already Exists".
Is something wrong with that code below:
<title type="text">Contact: </title>
<Contact xmlns="http://ws.constantcontact.com/ns/1.0/" id="https://api.constantcontact.com/ws/customers//contacts/101">
<ContactList id="https://api.constantcontact.com/ws/customers//lists/10" />
The XML that you have is the minimum you need to create a contact from scratch. In order to remove a list from a contact and add a new list, you need to do an update on the contact that already exists.
The way to do this is to do a GET call on the original contact, which gives you their XML. Then modify the XML so that the contact list node that they have changes from the one they are in to the new list. Then you would do a PUT call to the contact's URI (eg: https://api.constantcontact.com/ws/customers/username/contacts/12). This will update their information to have them in a new list.
If you have any questions about this please let me know.
Doing a PUT command updates the contact, it should not tell you that it already exists. Is it possible that you can send your code to the webservices support team and we can take a look and see what is going on?