Netstar is dishonest

Netstar send me contract for my new deduction and when they deducted they took extra money, i have already 4 reference numbers and still waiting for then to came back. i phone in then they said they will look into it. this is was the amount that was contracted by them and i accept and now they took extra money. so how must i trust a company like this and to trust them with my vechile... can somebody please give me answers.