Can call them to ask to switch to switched mode, the u can use ur own wifi router.

Yes, it can be served as a switch technically if you know how to do bridging.  You will need to create one additional WAN interface.

1. Identify the port that is used to connect to your old router. For eg Port 1.
2. Create a new WAN interface as bridge mode . Untick any VLAN option. Tick Port 2 and Port 3 , and those SSID ports if you want to make use of it as additional access point.
Why I leave Port 4 empty is, you will need that to access the Time router.

Connect another cable from your LAN port of your own router to Port 2 of the Time router.
The outcome form this setup is, for any device that is connected to Port 3 or the SSID from the Time router,  it will obtain the IP address from your own router.