Ticketmaster has asked for fans to be patient as it works through the applications for One Love Manchester.
Ariana Grande, Little Mix and Justin Bieber are among the stars at Sunday’s concert, which will benefit the victims of the Manchester suicide bombing.
Fans who were at Grande’s show on the night of the attack have been offered free places to the benefit gig.
In a statement, Ticketmaster confirmed it has allocated 12,000 tickets to such fans so far, out of 14,200.
But on Thursday the company said it had also received 10,000 “unscrupulous” applications for free places from people who did not attend Grande’s concert.
Latest statement from Ticketmaster
“Overnight, Ticketmaster processed a further 4,000 tickets for genuine fans, which is a total of 12,000 now processed out of the 14,200 we have set aside for genuine fans who were at the show on 22nd May.
“We urge all customers to check their inboxes, especially junk and spam folders, and claim their tickets by 2pm Friday.
“Registration has now closed, but we would like to reassure customers that we are still working through hundreds of applications and if they can verify that they were at the original show, they will get their tickets.
“There is a small number of instances where customers have not received their confirmation, however our customer service team continues to work extremely hard to contact customers as soon as possible and we ask for patience whilst we work through this.
“We will not stop until we have as many genuine fans at the show as possible.”
After setting aside 14,200 places for attendees to Grande’s original concert, Ticketmaster made about 35,000 further tickets available to the general public on Thursday morning. They sold out in 20 minutes.
But within hours some started appearing on secondary ticketing websites – which gives touts the potential to profit from what is supposed to be a charity event.
eBay told the BBC it was removing them as fast as it could.
“All tickets for this event will most certainly be removed by the team who are doing manual sweeps to pick up any that slip through,” the company said.
“We also aren’t allowing the sale of any item which profits in any way from the tragedy in Manchester. All of these items are being removed if they appear, and the sellers’ accounts will be restricted.”
Seatwave, Viagogo, GETMEIN and Stubhub have also stopped tickets from being listed.
Broadcasters in at least 38 countries have confirmed they will screen One Love Manchester live, despite the time zone differences.
TV networks in China, the US, Brazil, France, New Zealand, Canada and Australia will broadcast the show.
In the UK, BBC Radio 1, BBC Radio 2, BBC Radio 5 Live and BBC Radio Manchester will all broadcast the concert live, in a programme hosted by Scott Mills, Jo Whiley, Phil Williams and Becky Want.
The concert will also be televised on BBC One and streamed live on the BBC iPlayer.