BAD SERVICE

I have send my suzuki Gsxr 600 in for a faulty rectifier they replaced it and phone me my bike is done .I went to go fetch my bike and the F1 code was flashing on my dash i went to the workshop and the could not get the problem. I send Rob Gragg a email and he told me to bring the bike back so they can have a look. I went back the monday morning and the were busy with my bike for 4 hours and then told me sorry we dont know why the light is on and how to get the light and code off. I was not happy at all my bike went there with no code or light on i get it back with a code and a light on. I send Rob Gragg a email again and ask him what are they going to do to fix it and i said his workshop must go for training they dont know anything.its more than a month now and i havnt got any reply from them and its not nice at all to ride with a red light and code flashing in ure face the hole time