clicking when trying to start can indicate a failure of the battery (weak batteries will still play radios etc, but can’t provide the high amperage needed to energize the starter and starter solenoid). The starter or the starter solenoid may be defective. Tapping the alternator (if is that what he really did) should do nothing. Clean terminals and connectors, get that battery tested under load (how old is it? How many CCA rating? Many batteries have a useful life of just 4 years or so depending on what you bought. If you can put a jumper on the car and it starts right away, then you have a bad battery.