Deception and debit order increase

I have been with cartrack for 2 years and this year is the first time I have experienced the worst of it. After I bought a second vehicle I agreed via telephone to have Cartrack install dashcams within both my vehicles but to my disappointment, they were dishonest about the monthly premium. The first debit order different from the agreed premium. Whereas we agreed on what amount they would deduct, now they have increased the amount and took more than what was agreed upon. I requested that they downgrade but the cancellation/downgrade fee is even more absurd where Cartrack took in favour of one vehicle over the order even though the devices were installed at the same time