Faulty phones

I bought my mobicel berry at the end of last year January this year phone gave problems,i then thought it just need to have my updates done,i have since been having problems i cant send a simple email i then booked it in three weeks ago i got the phone back last week friday from mobicel and the phone is WORST!!I HATE THIS PHONE i have never experience this from any phone i had,im so dissapointed and to think i bought two brand new mobicels ?