iPhone SE 2020

I just received a refurbished iPhone SE 2020 and it arrived with zero battery. I charged it fully but have not activated it yet. By the look of the battery icon it has lost about two thirds of the charge in 8 hours while sitting on idle and picked up only twice in that time.

I will have to contact the company but just so I’m informed - could a battery lose more power than normal before activation? Should I try activating it or not bother? Would it be better to ask for a new phone or just a new battery? Thanks.