Hiya. I have replied to your PM with all the info you need.
Yes, IPG certainly do exist, the mobile number on the tickets would be the personal one of the ticket seller you bought the tickets from. It's possible that the tracking number is invalid tho i'm not sure why. IPG certainly don't put ticket sellers on the street only to turn away the business they bring in, lol
Anyway this can be resolved easily. See my PM and i hope you enjoy your day!
Sorry for the inconvenience you've had so far.
29/12/06 UPDATE: I have spoken to the customer in question today and they have now been able to make their booking. DF have given them 800 free paintballs by way of an apology for the inconvenience. The call centre think the problem occurred because the customer was trying to book a site which was not the closest site to their postcode. This generates a pop-up prompt to alert customers that there is a nearer site and we think that the customers firewall or popup blocker was interrupting this prompt. It's something our IT guys will look into after the xmas holidays anyway.