hard to help what can we do realistically
did you do a pin through check with a buzzy multimeter?
i took one of my leads to bits once because i thought it had failed but it just wouldnt work on this particular car
do you not know anyone friends family with a punto you could try on to see if it works on theirs?
I've managed to find a friend with a punto and I've tried the cables with the adapter and it worked straight away.
What should I do now?