Ticketmaster Collector Ticket refunds/COVID

FYI - Got a refund on some tickets from Ticketmaster, due to their cancelling the concert because of COVID, and they didn't refund the €20 for `collector tickets' and postage.
I chased it, first they said they had refunded it, I told them to check their records. Then (without an apology) "we don't refund collector tickets". I told them it was contrary to both sales and contract law. They tried to rely on a clause within their "Fan Guarantee" section whereby they don't refund if you change/cancel your booking. I pointed out that I hadn't changed the booking, that they had cancelled the concert and that they were breaching my statutory rights as well as the aforementioned laws. They have now agreed to make an exception, in my case. Don't let them get away with it, even for small amounts.