I have LG l75c optimus zip. Why do my contacts sometimes multiply
Are you syncing contacts to multiple sources (Social network accounts, email)? I highly suggest only syncing to one Email account and then also make a soft copy that you can save on your computer. To fix those duplicate contacts, back them up first. After backing up use apps like Duplicate Contacts (link) and Contacts Optimizer (link). Used both apps before and worked perfectly for me.