Couldn't get it to work - set off my radar as potentially sketchy too – Mergix Duplicate Contacts Cleaner Review

I have a bad problem with duplicates in my contact list and this app came up in a web search so I figured I'd give it a try. I tried it on the web first, but got a little concerned when it asked me for my "AppleID and password", so I downloaded the app, hoping that Apple's normally good authentication APIs would help keep my info safe. But even on the local application it asked for an AppleID and Password which doesn't seem right. Just to be sure, though I did enter my AppleID and password (which I know is correct) and it wouldn't log me in. So I deleted the app and asked their website to delete my account. Going to go change my passwords now. Since I didn't see any other reviews maybe it's fine and nobody else bothered to do a review, but just in case it's new (and sketchy) I wanted to do a quick review.
Review by Bpitas on Mergix Duplicate Contacts Cleaner.