Errors on the cluster after the installing and they are charging to send send out a technician

They installed a tracker on my vehicle and suddenly the service light came on and sent them proof that the car was recently serviced and its not yet due for service. they want to charge me 500 to send out a technician what MADNESS is that?????? This is ****ty service and ******* i would not advice anyone to take CARTRACK secondly i can also bring up the fact that they consumed my petrol while installing their tracker i am going to take this further