Oeps, we forgot to pay...again

I am a service provider who went out of my way to do a training for one of the employees at Rand Water on her request as it was part of her PDP. I was informed that the training was approved and that payment would be made a week after the trianing that took place in April, on the 6th of May 2015. I have to date not receive the payment and after sending approximately 15 emails following up on this matter, making at least the same number of calls to both the head of Training and Development Asnath Ngba and the finance clerk Setjhaba Mosese. They have given three more dates that they would've made the payment and still not payment has been made. This matter has not been treated with respect or any urgency on their part and nothing is being done to sort out this payment. I am a small company and this non-payment is impacting my business not even to talk about the time I am wasting to follow up on this payment. It is a disgrace! Most of the time they do not even respond to the emails. I have not idea anymore on how to get any reaction from them as another week goes by without them making an effort to sort out this urgent matter.