Early termination fee after moving house and cancelling broadband

Hi all, I’m hoping someone can explain this because I’m getting nowhere on chat. I moved house last month and rang Nexora to cancel my broadband at the old address. I was told there’d be an early termination fee because I still had 6 months left on the contract, fair enough, but the amount on my final bill is way higher than what I was expecting. I was quoted around £86 on the phone, but the bill shows £141.72. I didn’t add anything extra and the router was sent back using the returns bag. Can anyone tell me if that sounds right? I feel like I’m being charged for time after I’d already asked to cancel.