Sports fans will have to wait an extra two weeks for the chance to buy tickets to the Rugby World Cup, while those wanting to go to the Commonwealth Games have also been besieged with problems due to failings with the Ticketmaster website.
The company, which describes itself as the market leader in online ticket purchasing in the UK, has said it is undertaking an "urgent review" after it was forced to suspend ticket sales for the Glasgow games earlier this week.
This was followed today by the announcement that tickets for the Rugby World Cup 2015, which were due to go on sale tomorrow, will not be available until May 29 to give the website more time to test its ticketing system.
Tournament organisers England Rugby 2015 said in a statement: " The live sale date has been moved from Friday, May 16 (tomorrow), following a request today from Ticketmaster for more time to test the online ticketing system they are providing to ensure that rugby fans have the best possible experience when booking tickets.
"The new sale date also gives rugby clubs more time to register their members on the system for the 500,000 tickets available.
"The rugby community ticketing programme will now run from May 29 to July 2, 2014."
People wanting to buy tickets for this summer's Commonwealth Games were faced with long delays and problems with transactions earlier this week while it has emerged that callers to the ticket line were charged while listening to the engaged tone.
The problem has been blamed on a "human programming error" and Glasgow 2014 said it was working to refund the charges to affected customers "as soon as possible".
The website and phone line have been closed while the issues are investigated and could remain shut for days.
The Daily Mail reported that some customers ran up bills of more than £100 while trying to buy tickets through the hotline.
Responding to the Commonwealth Games ticketing fiasco, Ticketmaster UK chairman Chris Edmonds said: "We are undertaking an urgent review to enhance the performance of the website and improve the customer experience and we are confident the ticketing site will re-open very soon.
"We would like to thank customers for their patience and understanding."
A Glasgow 2014 spokesman said: "Glasgow 2014 can confirm that some callers to the Glasgow 2014 ticket line who received an engaged tone on the ticketing phone lines were charged in error by TalkTalk Business, a supplier of Ticketmaster.
"We apologise unreservedly for this and are working now with Ticketmaster and TalkTalk Business to ensure customers affected by this are refunded these charges as soon as possible."
An extra 100,000 tickets across all 17 sports and the opening and closing ceremonies went on sale on Monday but the company requested a suspension of the programme the following day with only around 55,000 being sold.
A TalkTalk Business spokesman said: "It has come to our attention that due to a human programming error, we did not deliver the service that had been agreed with Ticketmaster during the general ticket sale for the Commonwealth Games.
"This meant that some customers who called the Commonwealth Games ticket line and received the engaged tone were charged for the call costs in error.
"We would stress that this issue did not affect all callers to the ticket line and we sincerely apologise for the inconvenience this has caused. We will work with Ticketmaster to urgently compensate all customers affected by this error."
Around 2.3 million applications were made for the initial one million tickets released last year, with athletics, aquatics and cycling proving the most popular events.
BT said it alerted some customers about their calls to the hotline after noticing " unusual or excessive usage".
"In this case, although the caller didn't speak to anyone, the calls were connected to the receiving number and the relevant charges were correctly raised," a spokeswoman said.