Frustrated Andrea Bocelli ticket holders are putting mounting pressure on concert promoters Vipco to officially confirm a new date.

Despite announcing two weeks ago that the concert had been rescheduled for July 10, last week Vipco's Mike Dandridge and Darren said they were not "100 per cent certain" the concert would go ahead on that date.

Monica Thornton, 32, of Bicester, is one of many ticketholders who cannot make the July 10 date, and says she has left countless messages at Vipco's office in High Street, Islip.

Although she spent £186 on two tickets months ago she still has not received them and is now considering chasing a refund with the help of Trading Standards.

She said: "I spoke to Mr Dandridge many weeks ago and he promised me a refund as I will be in Italy throughout the summer. That call was some time ago and I have left several messages and sent emails since then, but have heard nothing."

Callers to Vipco's offices are now greeted with the following BT message: "Sorry, the part of BT Callminder belonging to this number is full and cannot accept any more messages."

Vipco has until June 10 to make an application to Oxford City Council for its public entertainment licence.

City council spokesman Louisa Dean said: "We are still waiting to hear from Vipco to confirm another meeting date."

Mike Dandridge was unavailable for comment when the Oxford Mail called him yesterday (Wednesday18.