I had this happen several times when using the cloud to store my contacts. Somehow it just makes duplicates or even more. I quit using cloud and use Gmail to back up my contacts exclusively and haven't had the problem since.
I would guess you're using an android phone. I had this start happening to me when I upgraded to Lollipop earlier this year. When they introduced linked contacts, it looked like more contacts were exposed that used to be hidden. For example, I had 10 contacts for every one and they all were in the WAZE address book. I solved it on my phone by going into the contacts settings and setting up a custom display to not display the waze contacts.