bad services and empty promises

I took my sony Ericson m4 aqua for a replacement screen witch was fitted . it took very long for them to repair , when I got it back .it had problems with the display . I took it back and waited months for it to be repaired but they told me its un repairable . they told me that they will refund some of the moneys . various times I called I was promised a call back . even today I was promised that I will be called in 5 minutes . phoned back and was told the manager is on the phone . i'm suspecting that he will not call at all . its easy 6 moths now but they are stalling . there contact number is