MTN - What a Shame

Use MTN for over 10 years. With contract renewal of sim only for R119 per month they want to charge me R150 for the renewal and then sign a debit order for R860 maximum per month instead of the R119 as due based on the contract. I can accept that due to the contract they can block amount exceeding the R119 and because they invoice in areas the outstanding amount could maximum be R 238. Any additional cost above the contract usage is anyway dependent on top-up payments in use, It just don't make sense and is derived from any logic. Under the contract the monthly payment was R119 which now suddenly increased to R160 while they use the same debit order to subtract the money from my account. What a shame.