Incorrect Debit Order amount every month

I took out a contract with Tracker and as per the agreement the debit order amount was R70 per month and ever since I took out the contract have never paid anything less that R85. one month its over a R100 and other months R95. <br> <br> I will cancel this debit order and take out another contract with people that can perform according to the promises made. Tracker is already in breach of the contract hence I am entitled to cancel at any time.