I was with Telstra and changed to Optus , Telstra was unhappy when I asked them to transfer my phone number to Optus . So keep your number , transfer to another carrier and No need to inform those you are signed up with .
Pleased to hear about your success , back in 2017 when I was 67 it took me over 6 months without any any income to get the pension, this was about misty bank accounts that I had to prove were not mine,good old Centrelink: