TPG won't allow me to cancel my account

[buhl247ey]

I upgraded from ADSL2 to the NBN with TPG on the 14th of Februrary and since this date TPG has not provided me with internet service. NBNco have been to my premises twice and confirmed the fault is TPG's. I wish to cancel my plan with TPG so I can use another service provider but TPG is leaving me on hold or closing my chat requests when I ask to cancel. I cannot receive internet from a new ISP until TPG allows me to cancel. I also wish for a refund for the 40 days TPG billed me without providing me a service. 

[buhl247ey]

You continue to close the chats that I create to proceed with cancelling my account. How am I suppose to progress my request for cancelling? Making it this difficult to leave the service is disgraceful. I have sent am email to cancel.tpg.com.au (it ridiculous I need to do this on top of liaising with your staff through comms channels), and still have had no reply.