Poor Service

I'm moving soon, so I was advised that I need to cancel my current fibre package and re-apply for fibre under the new address. The new property has a fibre box installed already, so I migration needs to take place. I've been battling to get anyone to help me or even just to call me back. The only message I got was that the migration could not take place because another service provider is still linked to the box. I have confirmed with the previous owner that they cancelled their fibre in January already, so I'm not sure what else to do. Would be great if someone could do something about this. This shouldn't be so difficult.