Cancel NBN Service

Level 2
I have been trying for weeks now to contact TPG to cancel my NBN service due to relocating and have been told via your online chat system that no one is available to speak with. I have been charged my monthly fee for a service I have not been using. Please advise who I can call to action my request. I understand your services may be limited due to COVID-19 however I'd greatly appreciate someone's reply so I can sort this out asap.