Excel cleansing

Description of excel work: I have lists of email addresses, but no other contact details in many cases. I'd like someone to deduplicate all the lists, and then using the email addresses, add a first name in a separate column where possible. For example, bensmith@btinternet.com would have the name "Ben" in the first name column. a.jones@jonescompany.co.uk would have nothing in the first name column because it's not possible to work out the first name from the email address.

The end result is to have a list of email addresses I can send personalised mail to using the first names that have been extracted.

The lists will total about 30,000 entries, but I suspect at least half will be duplicates
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