how do i cancel a cancellation for a sim in my phone

want to keep my current sim as I have changed my mind about switching

The window until the cut off (30 days) hasn’t happened yet so I assume I can cancel the cancellation?

 any reply would be appreciated as the chat bot doesn’t work for me (tried on two different devices, networks and browsers - plus I don’t know what option to call on the selection menu on the dial up assist)