Firstly. Is the battery properly charged?
The below table is the open circuit voltage after being stood overnight: If the battery is below 12.4volts it will suffer permanent damaged from suphation if left like this for long periods.
Just jump-starting the car and useing the alternator to charge it will NEVER fully charge the battery (unless you drive around for 24hours non stop). If you ever suffer a flat battery the car must always be put on a mains battery charger - how long depends on the charger used and battery size/state of charge.
Some "dumb" chargers if left on too long will damage the battery. Some automatic charger can undercharge the battery. However a 3/4/5 stage intelligent charger is simply a case of waiting for the green light (this takes two days on my Golf...due its huge 90Ah battery). Charging info can be found here:
http://jgdarden.com/batteryfaq/carfaq9.htm#types
Finally, the tracker; ignore the call centre lady. She knows squat about automotive electrics. Fact; a tracker with a faulty internal battery will drain your vehicle's battery. I've worked and disgnosed on cars suffering from this fault and after disconnecting the tracker's power supply the problem was rectified.
Either way, if its an old generation tracker, the maximum the car will stand unused is about fithteen to twenty days. If the car is used for short journeys, this will be less.