Acer — White Dot on Screen in 2 days of purchase but company noy ready to repair.

I had purchased a TFT monitor Model No. ACER and in 2 days after the purchase , I found a white DOT at the centre of the screen .
When the service personals came from Redington for service after continuous reminders for nearly over a month they told me that it is not repairable and they will not replace the screen as there is only one dot.They say that they will repair if there is more than 4 dots.
I dont know what is the logic behind this.
Really regret buying the product.