Useless company

I have 3 contracts with this company. In the 2nd week of December I get a sms from Cell C, saying my debit order is going to go off my bank account on the 27th of December, there is no opt in or opt out. This is going to happen. The problem with this is I only get my salary on the last working day of the month, not 1 day before, in this case, on the 31st of December. I phone Cell C customar services and explained my problem to the lady. During the course of the following week I get a sms from Cell C saying my payment arrangement was approved. What payment arrangement, they deviated from our agreement. So, the stupid that I am, I believe and trust this company. Come the moring of the 28th of December I get a message from my bank saying my account is overdrawn. I had a little over R800 in my account to carry me to payday, the 31st, but now I am in a minus. I am left with not even 1 cent until the 31st. I can not even buy a bread, plus I am going to pay R150 penalty at my bank for the debit order that went off without sufficient funds. Will Cell C refund me this, I am sure they will not. Thank you Cell C for srewing me. I have been a loyal customar for more than 20 years, but no more. I will not renew any contract of mine, I do not have to put up with this.