Poor service, and bad administration of payments

I have been a client of MTN since cellular networks first came to SA, and I have beena contract client. Last month, as with every month, I madean EFT payment for my contract fee That payment was R800 (on 24/4), and another payment of R100 on 3/4, neither of which are credited to my account. This morning, 25/05, with no other warning, I receive a sms advising that I have been cut off as I was short paid by R60.18. I was not in arrears at all, as these other payments would put me way ahead... !! 8 minutes later I receive another sms, advising me that they still have not received my payment, and will now be handing me over for legal collection. I hade to print out my payments, and go to the store to sort out... I am re connected, but cannot understand why these payments did not reflect... and why there was no apology... just a shrug... !!!