Combining/merging rows when a common e-mail address is found

I am having trouble drilling down a database of contacts that was recently passed on to me. Each contact can have up to five different phone numbers. Rather than having one entry per contact with all of the phone numbers itemized normally, anytime the phone number count exceeds one, a new entry is created for that contact with all identical information with the exception of the number. So for example, my table may look like:

Contact e-mail Phone Fax Cell
[email protected] 555-1234
[email protected] 555-4321
[email protected] 555-6789

I am trying to get a piece of code that can go down through the contact email, if the preceding cell is a duplicate move the phone number value up one row, delete the secondary row, and move on to the next row. My spreadsheet has about 4700 rows, so any automation tips that could be provided would be greatly appreciated!