How does another ISP get involved when we have never had or applied for fibre previously ? Only Vumatel and Openserve in the area. Hmmm may be the evil Telkom is behind all this. They keep on phoning to ask us to migrate to their fibre.
It's easy really. I can now place an order with an ISP for a random address. As soon as their system places an order and calls me I can just say ohh wait let me talk to my ISP first because maybe I will cancel the order I'm not happy.
That order will be stuck on the system as "Scheduling attempted" until the ISP rejects that order to free up the address again. Since orders are placed via API in most cases it won't raise an alarm with the ISP that placed the order as an order is placed and the system will take it from there.
You can even in some cases have where your neighbor places an order using your address and by mistake the installers continue and installs at the correct address with this order. That will cause your address to be blocked from placing any other orders as there is an active service on that address.