Vodacom Home Fibre Payment Disaster

Vodacom Fibre took over our complex internet fibre service. The handover was very poor and left us without service for days. Once this was reconnected the trouble started, Vodacom is failing to receive payment for the service by not putting through the debit order. For months we have requested them to process the payment but they don't, but continually sending an invoice that is escalating. When we call them all that happens is being transferred from one department to the next and eventually being told they cannot process the payment, or just have the call cut. How much longer am I expected to chase them to take payment?