What it needs to be done here?

Hello,

Myself and two other friends have moved into a flat in London in 2024. We were all students so exempt of paying council tax for this matter. October 2025, one of our friends stopped being a student while myself started a masters degree and the other person is still an undergraduate.

We’ve received a revised bill on October 2025 (of about £600, split in 3 payments until March 2026) with student discount (myself and the other student) and the bill for the other person to pay (council tax letter is in their name in this revised bill).

We have never agreed to pay council tax because we were student so we only split household bills equally.

The non-student flatmate is not understanding that we are legally exempt of paying council tax, therefore, we don’t need to contribute to that bill as the charge only exists because THEY are not a student anymore.

What can be done on this as I won’t be paying it because i’m exempt on this?

Any advice? Recommendation?

EDIT: We’ve got an email from the council saying they are the only person liable for the bill.