Switching from broadband to NBN required a credit ...

Switching from broadband to NBN required a credit card for some reason - couldn't proceed without it, but was assured that nothing would be deducted and that I could still pay via online banking.
Immediately after the call, I get an email saying that monthly payments would be deducted from this credit card, and a second email saying that $89 has just been deducted - what? I wasn't even told of this charge, let alone authorised it!
Called to complain and a supervisor needs to return my call, three hours later and they call my wife's number (what?) and leave a message that we cant even understand. The first opportunity I get I'll be moving, hopefully home 5G is here soon.