Cut off with no fair arrangement

We just received sms that our debit order was unsuccessful. We had funds in account till even 17th yet they did not deduct prior 13th,14th since 15th was Sunday. Now we get threats which I will add now via sms they cutting us off. This is first time in 16months with the this treatment. I am not only disgusted but also angry that they don't make any arrangements for a payment. They merely demand a payment from us. We are paid monthly 15th for my wife and myself 25th. The threats are unacceptable as well as the lack to arrange a payment. And here I liked CellC till today!<br> \Your Cell C account is in arrears by R344. Services to be suspended on non-payment in 2 days (Ignore this SMS if payment is already made)"...\""R70 will be charged for returned debit orders. Pay at: Nedbank"