I told I was losing my mind as well. I only wanted to change address. I did ring them, I was on hold for a while as the lovely was trying her best to help. I was put on hold for while (where I assumed she was speaking to a manager or something) before they told me I needed to log out and back in again.
looks like they did something technical on their end, but I’m happy it was sorted.
the lady mumbled possibly technicalities that may have caused the ‘make changes’ option disappear:
bills not paid
logging into the wrong Tesco account held.
this was like a ‘duh’ moment but after going over and over the account, they sorted it.
I spent 1hr 57mins on said call
i hope you get it sorted soon