Battery exploded

Me and my buddy were factory resetting the legion go as I was selling it to him I leave the room for a second to use the bathroom and I come back to see my friend holding a smoky fizzing mess shouting "SMOKE SMOKE SMOKE" I quickly opened all the windows in my house and told him to throw it outside

Id like to get some support from lenovo however they require my serial number which I obviously cannot access what do I do?