can your iphone be hacked into?

[Marlene]

So this is kinda a long story but pretty much this guy got my number started txting me and was being kinda creepy so i stopped replying then he started calling me i had enough and i blocked him on every social media and blocked him from txtin or calling me. today i get an annonmyous call trying to be a prank call i kept asking who it was they said they would call me from their number later, around 9 i get a call and the caller id is the initials of the guy i blocked. but on my phone his full name was saved i looked for the decline button but there was only option which was to pick it up so i just let it ring after that i check my recent calls for his full name which i had bloacked and its not on the list i look in my phonebook and its like it never existed but i know that if u blockk ppl there contact still stays in ur phone just in case u want to unblock them anyways i look at the contact which was his initials and it said it wasnt blocked i quickley blocked it. so my question is it like possible he hacked into my phone deleted his old contact and put a new one in or something like that