Just ask straight up. If they don't listen, and it's that important to you, then leave.

I got a raise at the end of last year, as I do ever year. When they told me what the raise was I immediately responded by saying "That's less than the rate of inflation, this is essentially a pay cut."

And when there was an opportunity to ask questions of the executives I asked "My raise, and I assume the raises of many of my co-workers, were less than the rate of inflation this year. Will you consider cost of living adjustments to our compensation?" The answer was usual business speak about paying competitive market-rate salaries and whatnot.