Lost Mode lock, No support?

Hi guys,

I'm going to post this here in the hopes that someone here has been through my situation

so about a month ago, my friend's phone broke, so I was going to lend him an iPhone 7 plus I had lying around. However, it was stolen from me the day I was going to give it to him when my gym locker on Campus got broken into while I was working out. I pretty much lost my laptop, some school notes and the iPhone, which had been wiped the day prior.

I went to CS and pretty much told them what happened, and asked them to contact me if anything turned in. About half an hour later, while I was trying to sort things out with my carrier, CS pretty much contacted me saying that someone had turned in some of my stuff (my school notes and the iPhone 7 plus, but not the laptop). I then told my friend that I'd have to give the phone to him the following day so that I could sort thing out.

Fast forward a little bit, and I go to turn on the phone, and realize it's been setup and put in lost mode with no message. This seemed kind of strange, but I wiped the phone using iTunes and was hit with activation lock, and asks for an Apple ID that I do not recognize.

Doing a little bit of digging, I found myself contacting Apple and told them my situation. They emailed me some form where I had to submit my proof of purchase (which luckily I still had), and told me to wait about 7 days.

7 days go by, and then another 5 more, but still nothing. I contact Apple support again, and was again, asked to resubmit the documents. About 4 days later, I get an email from Apple saying to contact Apple for an update on the case.

Upon contacting them, they tell me that because the phone is in lost mode, Apple engineers can't do anything on their side and she told me instead to try going to an Apple store where apparently they have some sort of machine which can override lost mode.

A couple days later, I called them again to see what I should do, and this time the advisor told me that going to the Apple store wouldn't get me anywhere.

At this point, I have no idea what to do. I've been on the phones with Apple for about 4 weeks now, and can't seem to get any progress in this case.

So I'm wondering if there's any way I can reset MY OWN phone (with valid proof of purchase, ID and a bank statement) given it's lost mode status with an Apple ID that isn't even mine??

Please help

Thanks