@Rach04x This is currently how IDMobile operates and some other network's. It's easier to draw a customer in with what seem a good deal.
You may want to try IDMobile Live Chat log in with your detail's and in the message box type To speak to someone.
Our Live Chat team are available 9am - 8pm Monday to Friday,
and 9am - 6pm Saturday, Sunday, and Bank Holidays.
https://www.idmobile.co.uk/live-chat
The other option maybe to get a pay as you go sim on a different network and port your current number over to them. Once port completed reorder the package on IDMobile and port your number from the new network back onto IDMobile.
Most other network's your able to speak to a sales agent or management to negotiate a deal which I've done on all the major networks in the past.
Joe