Car Insurance

I have insured my car with Santam and my premiums are inclusive of Altech Netstar Tracker. I have since received a call from Blakes and Associates informing me that I owe Altech Netstar for over 6 months. When enquiring with Santam they say the contract has changed and I should pay Altech Netstar directly. They have never informed me of the changes and the premiums have increased instead of crediting my account. I have spoken to one of their consultants and to date he has not resolved my query. The Blakes and Associates consultants keep on harassing me with their calls.