I had contacts that showed up double. It seemed that if someone had 2 different emails or 2 or 3 different phone numbers, that there were separate entries for each. I just manually went through all my contacts (yes it takes a LONG time if you have a lot of items entered). But since I was in the hospital when my fiance got me the phone, I have plenty of time on my hands =)
I don't know about deleting your other gmail account tho.
Good Luck!