Damaged cellphone

On the 19th of November 2021 I purchased a Nokia C20 Sand Gold D's N1 and after a day of purchase I experienced problems ,went back to report it and a gentle assisted me with factory settings and a software update still I had problems ... At Jet they said they would call me and assist with Nokia settings but until today I have not received any call regarding settings or what so ever though they took my details. It buffers the screen automatically changes itself ,when I receive a call it rings but not show who is calling nor gives me a platform to answer until it stops ringing , when I'm using the internet while busy it cancells itself and go back to main screen and when ever I'm using the apps and I am done and go back to main screen it always pops ring tone volume app and it disappears quickly after that, also the keyboard takes time to pop up and use I have to tap on it several times before it works...

Please can you assist because I need to change it or get my refund back as I am not happy with this phone everyday it gives me problems and no joy