The man is wrong.
O2 do NOT offer blackberry services on PAYG.
SIM Only (Simplicity) Plans, where you pay monthly, but its not a fixed length contract, do have blackberry services bolt-ons.
Call O2, ask for technical support and explain your problem.
"That's it then. Cancel the kitchen scraps for lepers and orphans, no more merciful beheadings... and call off Christmas."