Tracjer instalation

A tracker unit was installed in my car 14/3/2020 the technisian told me the airbag light is on and he needs a masjiene ti fix it, he will be comming to my hometown in the next week to fix it. On my way home i saw that my feul economy is working the other way araond on a uphill im getting 30 l/k and a downhill 2 k/l with my foot of the exelerator. My cars auto hold on the handbreak suddenky did nit work and the handbreak auto engage akso dont work. I have reported this to cartrack customerbcare and i only hear ill be contacted. Yet no one has contackted me. This intalation cost me more than 800 rand and now i get ni satisfaction from this company.