Unfair Billing

I took a tracker with Altech, in 2010 when I bought my car. My contract with them was for 2 years. I paid them every month for two years, never have I ever skipped a payment with them. The contract ended after two years, they continued billing me for a service that I finished paying for without them telling me that they will do that. I decided to stop paying, they handed me over and I no longer have a contract with them. I would not recommend Altech Netstar to any of my friends, they are a *******.