Vodacom order and cancellation process a nightmare

We placed a fibre order with Vodacom and we decided to cancel the order after a back and forth with the delivery guys because they refused to call us before coming to the house after asking them to make arrangements with us on time so that there is someone to receive the order. We have since placed an order with another internet service provider and for some reason Vodacom will not release our line and we are unable to place an order with any other provider. We have engaged Vodacom on multiple occasions regarding the cancellation and do not understand what the issue is because they actually failed to deliver and we did not have an actual service with them. The entire process has been a nightmare and is really unfair. Release the line!!!!!!!!