Viagogo, the official secondary ticket partner for the Michael Jackson O2 arena shows in London, has begun the process of refunding fans who paid for tickets via the online platform.

It is understood that tens of thousands of tickets were sold on Viagogo with the bulk of them at prices ranging from £300 ($492) to £400 ($656) each.

Everyone who bought a ticket will be sent an email with a unique link, which will start the refund process. Anyone who has not got the email by July 6 is advised to contact Viagogo's customer services department.

The same process applies for Viagogo's official VIP packages for the Jackson shows, which cost between £700 ($1,150) and £800 ($1,300).

Fans can also choose to have the souvenir ticket, which they would pay for in full in the same way as those who bought tickets in the primary market.

"Everyone at Viagogo was deeply shocked and saddened by the recent news of Michael Jackson's death," says a statement on the Web site. "Our thoughts continue to be with his family, friends and of course his legions of fans around the world."

Eric Baker, founder and CEO of London-based Viagogo, said although the refund process is a big operation, it is simply a case of returning fans their money directly.

"The way that we run our business here at Viagogo is that we hold cash until the tickets are printed and everything happens," Baker tells "Therefore the whole purpose of our service, unlike an eBay or other places, is that we're just reversing the cash back."

The Jackson tickets had not yet been printed and sent to the original buyers.

Baker adds that users do not have to fill out forms or complete an insurance application procedure.

Viagogo's policy is not to transfer any money to sellers until tickets have been printed and successfully sent to the buyer.

"By doing that we protect the people in the system, it allows us to give the cash back because we never want to be in [that] situation," says Baker. "We always want our customers to know that if there is any problem, they don't have to deal with any third parties or third party seller or an insurance company. We're actually going to reach out to them."

Baker declined to reveal details of the number of tickets sold on Viagogo or the prices paid, citing confidentiality as part of the partnership with AEG Live.

In the event of other events being canceled in future after tickets have been sent out and money had been paid out by Viagogo to the sellers, Baker says fans would still be refunded. He says that it would not be dependant on the money being recovered by Viagogo from sellers, although Viagogo would seek the return of that money.

"The bottom line is from the customer's perspective, they're always covered on Viagogo, they're going to get their money back," says Baker. "We have every seller registered. We're a sizeable company, we can stand behind these purchases and we have systems in place to deal with it."

Baker sold his U.S. ticket exchange company StubHub to eBay.

In a statement, eBay said it is "committed to ensuring that no buyer is left out of pocket" on eBay and "will ensure all buyers on the site can receive a full refund for their ticket purchase."

The statement added: "On this basis, eBay and PayPal is extending its Buyer Protection to all Michael Jackson concert ticket purchases bought on eBay. The company will also help sellers by refunding eBay's sales commission when they refund buyers for Michael Jackson ticket sales."

Further details of how buyers and sellers can work with eBay and PayPal on refunds are set to be announced.