You can't freeze prepaid services, the clock continues to run.
The only thing you could do to keep it working, is to keep topping it up.
"Am I able to put my plan on hold?"
You normally park the number then cancel the plan.
Parking involves porting to a Telco that provides that option for a reasonable price $10 (not Optus I'm afraid).
Read about how here (its very straight forward)
Sign up to any plan you want when you return.
Hi @ERich284, you can definitely suspend your post-paid service with us. You will need to speak with our billing team either via the → messaging service or by calling them on 133937 - Mon - Fri: 8am - 8pm Sat: 9am - 5pm AEST to process this for you. Unfortunately, we don`t have access to customers account on this public forum.
@Kartika - Suspending still charges customers, please read the customers post prior to proposing solutions.