If you're entitled to money back under your club's cancellation terms, it comes back in one of two ways:
You paid within the last 6 days: your money was still on hold and nothing was charged. The hold is released and the pending amount disappears from your account within a day or two. You won't see a +£ amount.
You paid more than 6 days ago: your payment was already charged on day 6, so you get a real refund. You'll see a +£ amount, usually within 24–48 hours.
Your own timing is what counts
The 6 days run from when you paid, not from when the booking was created. That's why two players on the same booking can see different things — one gets a released hold, the other a real refund. Both are correct.
If you leave a court booking where players pay their own share
Leaving doesn't immediately change what the lead booker is charged. The final split is calculated 4 hours after the session's end time, and their amount is adjusted then.
Whether you get money back at all is decided by your club's cancellation policy, not by Nettla. Check your club's terms or ask the club directly.