If Only

The best things in life are free, but I think it is best if you think of the welfare of your employees more than the image and the opportunities you are trying to protect and maintain for the longevity of your business. Let it be known that the services we have provided you has been so much, we feel that our compensation is no longer competitive.

I hope you consider giving us what we deserve this time, and that you value our existence as your ally, not just a trusted employee. 

Give it a little human aspect for a start. A pat on the back might help to start it with.