Worst Mobile phone I've ever had

I bought a Hisense E30 mobile phone on the 28 May 2020 , it has been not even 4 months and my devices battery is non existent . After a full charge with 15 minutes of use my battery would die completely not to mention if you were to see that the battery is anywhere less than 90% the phone would die even faster . To make use of my phone I need to keep a power bank charged at all times . It feels as if I'm carrying a landline . Utterly ridiculous