Truly outrageous behavior by the property, assuming that your rate is within reasonably normal. They've got you on a rate that, theoretically, you can't cancel. Then, at the last moment, they pull a bait and switch.
Just took a look at one random date for the property (+Feb. 6) and, voila, found a rate described this way: "Experience! Dining Package, includes full English breakfast, dinner at Fratelli"
Rate is inclusive of
- Overnight accommodation in a deluxe room
- Breakfast and Dinner in hotel restaurant for up to 2
people (1 dinner / breakfast in single rate / 2 in double
rate). Please ensure the right number of guests has been
selected to receive the correct rate. Additional Breakfasts and
Dinners will be charged separately.
Dinner will be available to guests in the Restaurant Fratelli
Monday - Saturday 6pm - 10pm

So, clearly the property has rates that include dinner and breakfast. I certainly would make an effort to speak to the General Mgr of the property. I think you need to talk to somebody at the property that has the authority to potentially right this wrong.