Poor service and communication

Mtn did not debit their money on my account for my contract last month which was 25 August 2019 . They did not even send me a notification to say what was the reason because all I know I have money on my account from the 25th until the 30th. Now they have suspended my cellphone number I don't understand because it is not my fault and I deserve to know the reason to why they did not debit and I didnt even get a massage stating that there were no funds on my account. They have no right to suspend my account. Right now I cant make calls I do anything and I use this phone at work. This is not how you deal with paying customers. I've have never missed a payment.