I passed on my 3rd attempt (Class 2) so do not worry about the amount of times you have failed, look at those as a learning session (yes the cost doesn’t help) and find another training centre, tell them what you failed on and concentrate on getting those corrected.
I hit the kerb on my 2nd attempt too. Pain in the arse doing it but whatever you think you may have failed on, don’t give up and keep going. You will get there. Once you have passed, you then don’t have to worry about hitting a kerb again 
Keep at it dude.
Also examiner wise, I had the same guy on my 2nd and 3rd test. 2nd one he said I was going to quick around roundabouts, 3rd time I slowed it down and he said after that I need to go quicker. You can’t ruddy win at times.