In fact it's common practice.
Your mistake was in going direct to Phillips, because they have no obligation to you under the terms of current consumer law. Your contract was with the retailer from whom you bought the monitor, and as the fault developed within six months of purchase the law would have assumed it to be there on the date of purchase - you would have been entitled to a replacement.
Because you don't now have the original monitor you can't go back to the retailer, and the best you can hope for is that Phillips will take pity on you and supply you with a new model. Have you fully explained the position to them?