For the voltage test, i take it that you used a neon screwdriver test pencil.
These are only indicative and i would not rely on a true reading.
As the service technician told you as well, these can lit up even when the power switch is off and just pick up inductance to light up the internal neon.
Your finger will act as the return patch for the few µAmps required to light the neon.
Neons will generally light up at voltages above 60 to 70 Volts ( striking voltage).
In series is a high megaohm resistor to limit the current flow.
On dc application only one electrode of the neon will light up.
I would use a duspol for a course voltage measurement between phase and neutral and earth, and to check for correct polarity from phase to an independant earth.
This imposes a load of about 100 mA on the circuit under test, by means of a coil and plunger with a flag for approx volts reading.
A DMM can be used for an accurate voltage measurement. It does sometimes pick up a voltage too because of its high internal impedance.
One lead needs to be attached to the neutral or earth, the other one to test for voltage on the terminals.
It is good and safe practise to test your meter before and after your tests on a known live source to check if the meter works.
I'm not sure what system you have in your country but it is important that the polarity at your power socket is correct.