Welcome to the Community!
In most cases, NBN technicians do have a master key for MDF access. However, there are cases wherein there may be additional security locks which they don't have keys for or they may need to go to a specific location outside of the MDF which they may not have access to.
We'd like to take a look at this case further for us to know what's required to get your service restored. I tried locating your account using your community details to no avail. Can you PM us your customer ID or TPG username including your address?
For your reference: How do I private message (PM) in the community
Thanks for providing the account details via email.
The technician that previously attended the appointment is from NBNCo. It was noted that they didn't have any access to the MDF, though there were no specifics given if it's due to them not having a key or what not. Please do coordinate with Strata or Building Admin to allow access to the MDF to ensure that the NBNCo technician gets the work done.