Oh, I just GOOGLED the hotel's website.
Hotels in Patong, Phuket: C&N Hotel Patong
Which indicates that the price is 1200THB per night in early December. So the price you are being quoted (1400THB per night) seems to have a surcharge built-in for breakfast.
I would just book through their website and specify that you want a 1200THB room, no breakfast, kob khun krap.