Don't want to replace or repair my phone

I had trouble with a phone I bought a phone last year august and early this year I sent for fix and waited three months for a phone that will come back to do the same thing I sent it away for I asked for an refund and they refuse they giving me excuses and delaying the process...I am missing out on important calls ...what they are doing to breaks my heart because I am a paying customer to be treated like this !