Hi Welcome to JustAnswer. My first response will follow shortly. Please feel free to follow up if anything is not clear

That would be an interesting damages issue. They have clearly breached the contract to advertise, so the damages must flow from that. I would think you may need a media expert to give you some idea as the losses.

There would be a finite period of loss from the expiry of the last ad to the replacement for 2013, which would have to be based on the lost opportunity. There could be some difficulty in calculating exactly what you lost however.

the courts have developed guidelines for assessing damage, and distinguish between certain or speculative damage. You may also need to show that you have mitigated your loss, perhaps by advertising in other ways, although being left out of the phone book, where they have a monopoly, would make it difficult to demonstrate how else you could have advertised your contact details.

In this sort of case the court would need to estimate the figure for losses, because the analysis of the loss of business would be very difficult. I am inclined to think the court would be cautious in fixing the figure, but it would be difficult to say how much. No doubt the publishers would also say your choice to change from bold to standard listings would have reduced your exposure as well.

But at the end, they had breached the contract, and you should be entitled to some compensation.