bad service

I bought a phone from jet according to them had to take insurance so we did ok in jan the phone was ****** did a claim said to the lady i want a good one so a month and a week later phone gives me a white screen cant do anything they send the pbone to finrite on the 3rd so this week i went and said whats going on so they phone o no the phone is there since the 4th but no paper work now really is it my problem so today i have been phoning and phoning them and stil no where. I need advice or answers i have been wasting so much money on calss to them and to jet and really i had to go and buy a new phone already because i need my clients to live