Up to 10,000 people were helped to seek a refund for invalid tickets during Ed Sheeran's UK tour, with just under 2,000 in Cardiff.
The Shape of You singer imposed strict rules for entry at his 18 gigs to try to stop the reselling website Viagogo selling overpriced tickets.
Tour promoter Kilimanjaro Live said thousands of fans with invalid tickets from the website were offered new ones at face value.
Viagogo has been asked to comment.
Sheeran had said he wanted to stop fans being ripped off by secondary ticket sites, many of which are believed to be used by touts selling at overinflated prices.
The majority of ticket resellers had agreed not to list tickets for the stadium tour but Viagogo did not follow suit - and fans who bought tickets from the company were told they were cancelled.
They were given a letter after arriving at the concert to prove they were invalid - which is needed to gain a refund from the reselling site - and then offered new tickets at face value for that night's concert.