Unable to upgrade package even if I offered to pay

So I have a package deal with you and it only give me 5GB during the day and 15GB night time which isn't enough for me. I've asked if I can upgrade to a 20GB day time data and I'm willing to pay whatever the rate would be to upgrade it to that. Unfortunately just because you don't offer such a package I can't upgrade. The only option is to get a completely different package for an ADSL line and pay the remainder of my current package if I want to cancel...which the contract is still on for another year so you've locked me in and offer me no alternative.<br> <br> Very unhappy as you advertise yourself to be able to cater to all needs.