I have two questions
1.I have more than 7 lists of subscribers in manage subscribers list how can I consolidate the list in to one?
2.There is some information missing on subscribers like phone number etc. Can I upload the list again and if it process finds the duplicate, will it update that contact with additional information or will it create duplicate?
1. If I understand you correctly, the problem is that you're adding a new list every time you want to add subscribers? Instead of clicking the "Create a new list" button, just click the list and click the "Add new subscribers" button. If you have 7 files of subscribers for one list, import all of them to that list and delete the rest. If you don't have files with the subscribers, you can export each of the other lists and import them to a single list.
2. You're right, re-importing a list will update all fields for each address.