Kitchen light wiring

the best way its to hire qualified electrician to do this job..its not diy..

If it is the 3 plate method T+E which I am guessing it is then one of the cables will be from the switch. Normally the black is marked with a sleeve, red if old colours. If you have a continuity tester (power off and safe isolation) you could test between the black and red of each cable operating the switch until you find it. One warning though if it has been wired wrong and gone bang the switch could be fused together, quite rare but have come across that. Once you have identified the black S/L from the switch the other blacks should be neutrals. Mark that black (S/L) with red tape to identify it for future. Should be straight forward from there.

It sounds like you have lost the switch live which will be one of the black cables. If you turn the power off and link out the red and black cables in the light switch you can then do a continuity test between all 3 black cables and the red cables of the light fitting. The cable with continuity will be your switch supply which needs to be connected to the live terminal of the light fitting. The 3x red cables at the light fitting will remain in a connector block not connected to the light and the remaining 2 black cables will go into the neutral terminal of the light.