Consolidate, clean and format 2300 contacts for MailChimp

I have 2 MailChimp accounts that need to be cleaned and consolidated. One account has about 500 contacts and the other has about 1800 (2300 total). They are formatted differently (different headers and content) and may have duplicate entries.
We seek a PPH expert to consolidate this into one single contact list including:
- no double entries
- consistent formatting
- appropriate tags and segments
- .csv file to upload to MailChimp

Demonstrated experience with MailChimp is required. Ability to complete this ASAP.