Tracker's negligence

On the 23rd of March2024, I was hijacked and held hostage for more than 2 hours. During that time Tracker sent me 2 messages regarding tracker tempering on my vehicle and no one called from tracker. They only realised that the car was hijacked when I reported it the next day. After few days I realised that the tracker was not working, I then called to report it and I was told that someone is going call and no one did. I eventually called in to cancel the contract and explained what happened and I was that told the contract is cancelled and I will not be debited again. After few days I received an SMS letting me know that the tracker is not working. On top of that there was document needed by the insurance of which I was sent from pillar to post to get. I ended up complaining and received the same day and the turn around was suppose to be 3 days. Now I receive an invoice for R1000 which I am being told it's the cancellation fee. If it wasn't for Tracker's negligence I wouldn't have cancelled the contract so I refuse to pay the invoice