delay date shown for removing iphone from Find My

Damaged phone covered by a third party service through a business account. Received the replacement phone, instructed to remove original phone from "Find My" before sending to the . We were leaving soon for a flight/cruise so I didn't have a lot of time. I went through all the steps for removing the phone from Find My and it still showed up with a "disclaimer" in the Find My app that said it would be removed on June 27, which was the next day. I tried several times in hopes it would immediately remove it, but it always gave that 24 hour delay. Eventually I gave up and decided to trust it, and sent it off since we would not be back before the deadline to send it. Now, several weeks later, I still see it in the Find My app with the disclaimer that it will be removed on July 20. I don't want to be charged with a 300 fee for not removing it from Find My. I also now have the option to erase the phone, which did not show up before. Do I erase the phone and trust that it will be removed from Find My? Or is there something else I can do? I've received an email from the third party warning me ...