Useless Dstv and useless installer

I called an accredited dstv installer to come and rectify an E143 error on my xtraview decoder and i was ****med out of R1700. the dstv telephonic assistants were useless and insistent on there being a connection error in my system. the installer "fixed" the problem and my decoder worked for 2 weeks, however now the very same problem has arisen and the installer is no longer taking my calls to come and rectify. the installers name is chris and his number is ***. dstv has told me to get an installer to rectify the problem again, how can this be if i will have to spend an additional R1700 and they say that they cant help me.....