Pictures and contacts

I am getting someone’s pictures save to my photo’s I didn’t take them also I found a person I don’t know and didn’t add saved to my contacts I bought a unlocked I phone 7 on eBay I thought it was new but maybe it’s refurbished it came with a few safe link minutes I didn’t even know would be on it . I used the same phone number on my old iPhone se as I use on this new one . Trying to find out if anyone knows if these problems are because my new iPhone 7 has problems or if I am getting these pictures and this contact person on my new iPhone because I didn’t have everything removed from my old phone and I am getting the person who owns my old phones pictures and contact