I just saw the instalment increase without anyone giving me a heads up

I just saw the instalment increase without anyone giving me a heads up. I later realised that theres a higher possibility that your tracking device on my vehicle might be off as I tried tempering with it no one phoned me from their side to check if everything is okay. I phoned on Monday to try finding out first call left me on the waiting until I gave up and then on Wednesday I ended phoning the technician who installed it which wasn’t helpful as he jobs ends there. This is last week So I wrote a very intimidating email then that’s when they started calling me back and they are attending to my matter which I believe and hope they will be done before the week ends