Welcome to TPG Community!
We have located the account using your community details and we can see that you have been in touch with one of our technical specialists who advised that it is okay to remove the battery back up as it will not affect the internet service.
However, we'd like to set your expectation that you won't be able to use the home phone service in the event that you experience a power outage.
Should you have further queries, please let us know. Thank you.