Hi @adibakabir, welcome to TPG Community!
You can check if there's a planned network upgrade or outage impacting the 5G services at https://support.tpg.com.au/network. If none, you can relocate the modem, near a window is ideal, to get a better reception. You mat also perform a reset on the modem by pushing the small reset button.
If same thing, you can send us a private message with your customer ID and we'll have a closer look at this for you.
Thanks,
Aubrey
