Back Market review: iPhone 15, bought in April 2025 and died in October 2025 from motherboard issue

iPhone 15 that I purchased in April of 2025 died in October 2025.
I took it to Ubreakifix and they said it was an issue with the motherboard and it would be more costly to fix it than the original $600 I paid for the phone from Back Market.
I reached out to Back Market, and they’ve been running me in circles for two months on their service chat in the app.
Back Market has been telling me that I still am logged in to my iCloud, when I followed their instructions to the t, before sending it back. I’ve done these same steps over 15 times! And still they say they cannot begin work on it until it’s been removed from my account. On iCloud, find my iPhone, and on the iCloud website, it all says that the phone has been erased and is not linked to my iCloud. It also says it’s offline and cannot be totally erased until it’s online.
I called apple this morning and they confirmed the iPhone 15 is not linked to my account at all and that IF Back Market was able to get into my phone, my account wouldn’t be associated with it. And if they’re not able to get on the phone, how do they know my iCloud is still associated with the phone?
I asked for clarification and what error is popping up, or a screenshot of what they’re seeing that tells them it’s still linked, and they just sent me a response saying they’re sending the phone back to me so I can log out of it myself.
I can’t turn on the phone and it doesn’t charge. How exactly would you like me to log out of my iCloud and erase the phone on a phone I am not able to use? AND that I’ve already done this over 15 times, and apple confirmed I only have two devices on my iCloud and the iPhone 15 isn’t one of them.

They’ve been running me in circles for two months because they don’t want to resolve the issue, and they’re making that blatantly obvious.
I highly suggest going to another company that you can purchase refurbished electronics from, because back market’s customer service is nonexistent, not to mention they sent me a broken phone that I paid over $600 for.